Welcome to yet another libgit2 release, this one being the
biggest we've shipped so far. Highlights on this release
include diff, branches, notes and submodules support. The new
diff API is shiny and powerful. Check it out.

Apologies, one more time, to all the early adopters for the
breaking API changes. We've been iterating on the error
handling for the library until we reached its current state,
which we believe it's significantly more usable both for normal
users and for developers of bindings to other languages.
Also, we've renamed a few legacy calls to ensure that the whole
external API uses a consistent naming scheme.

As always, check the API docs for the full list of new API calls
and backwards-incompatible changes.

	http://libgit2.github.com/libgit2/

Changelog of new features follows:

Attributes:
	- Added function macros to check attribute values instead of having
	to manually compare them
	- Added support for choosing the attribute loading order (workdir files
	vs index) and to skip the systems' default `.gitattributes`
	- Fixed issues when fetching attribute data on bare repositories

Blob:
	- Added support for creating blobs from any file on disk (not
	restricted to the repository's working directory)
	- Aded support for smudge filters when writing blobs to the ODB
		- So far only CRLF normalization is available

Branches:
	- Added a high-level branch API:
		- git_branch_create
		- git_branch_delete
		- git_branch_list
		- git_branch_move

Commit:
	- Commit messages are now filtered to match Git rules (stripping
	comments and adding proper whitespacing rules)

Config:
	- Added support for setting and getting multivars
	- Added `git_config_get_mapped` to map the value of a config
	variable based on its defaults

Diff:
	- Added full diff API:
		- tree to tree
		- index to tree
		- workdir to index
		- workdir to tree
		- blob to blob

	- Added helper functions to print the diffs as valid patchfiles

Error handling:
	- New design for the error handling API, taking into consideration
	the requirements of dynamic languages

Indexer:
	- Added streaming packfile indexer

Merge:
	- Added support for finding the merge base between two commits

Notes:
	- Full git-notes support:
		- git_note_read
		- git_note_message/git_note_oid
		- git_note_create
		- git_note_remove
		- git_note_free
		- git_note_foreach

References:
	- Added `git_reference_name_to_oid` helper to resolve
	a reference to its final OID

	- Added `git_reference_cmp` to compare two references with
	a stable order

Remotes:
	- Added support for writing and saving remotes
		- `git_remote_add`
		- `git_remote_save`
		- Setters for all the attributes of a remote
	- Switched remote download to the new streaming packfile indexer
	- Fixed fetch on HTTP and Git under Windows
	- Added `git_remote_supported_url` helper to check if a protocol
	can be accessed by the library
	- Added `git_remote_list`

Repository:
	- Made `git_repository_open` smarter when finding the `.git` folder.
	- Added `git_repository_open_ext` with extra options when
	opening a repository

Revwalk:
	- Added support for pushing/hiding several references through a glob
	- Added helper to push/hide the current HEAD to the walker
	- Added helper to push/hide a single reference to the walker

Status:
	- Greatly improved Status implementation using the new `diff` code
	as a backend

Submodules:
	- Added a partial submodules API to get information about a
	submodule and list all the submodules in a repository
		- git_submodule_foreach
		- git_submodule_lookup

Tag:
	- Added `git_tag_peel` helper to peel a tag to its pointed object
	- Tag messages are now filtered to match Git rules (stripping comments
	and adding proper whitespacing rules)

Tree:
	- Killed the old `git_tree_diff` API, which is replaced by the
	new diff code.

Signed-off-by: Vicent Marti <tanoku@gmail.com>

Break everything before the release

fetch: set dummy function for local fetch

Local fetch isn't implemented yet. Don't segfault on call, but set a
dummy for negotiate_fetch and terminate gracefully.

Reported-by: Brad Harder <bch@methodlogic.net>

branch: retrieve symbolic references when listing the branches

Consistency is good.

Profiling with scottg

Fix workdir iterators on empty directories

Creating a workdir iterator on a directory with absolutely
no files was returning an error (GIT_ENOTFOUND) instead of
an iterator for nothing.  This fixes that and includes two
new tests that cover that case.

This fixes a warning left by the earlier optimization and
addresses one of the other hotspots identified by GProf.

GProf shows `git_text_gather_stats` as the most expensive call
in large diffs.  The function calculates a lot of information
that is not actually used and does not do so in a optimal
order.  This introduces a tuned `git_buf_is_binary` function
that executes the same algorithm in a fraction of the time.

This fixes the examples so they will build and adds a PROFILE
option to the CMakeFile that enabled gprof info on non-Windows

Fix status for files under ignored dirs

There was a bug where tracked files inside directories that were
inside ignored directories where not being found by status.  To
make that a little clearer, if you have a .gitignore with:

    ignore/

And then have the following files:

    ignore/dir/tracked     <-- actually a tracked file
    ignore/dir/untracked   <-- should be ignored

Then we would show the tracked file as being removed (because
when we got the to contained item "dir/" inside the ignored
directory, we decided it was safe to skip -- bzzt, wrong!).

This update is much more careful about checking that we are
not skipping over any prefix of a tracked item, regardless of
whether it is ignored or not.

As documented in diff.c, this commit does create behavior that
still differs from core git with regards to the handling of
untracked files contained inside ignored directories.  With
libgit2, those files will just not show up in status or diff.
With core git, those files don't show up in status or diff
either *unless* they are explicitly ignored by a .gitignore
pattern in which case they show up as ignored files.

Needless to say, this is a local behavior difference only, so
it should not be important and (to me) the libgit2 behavior
seems more consistent.

notes: make git_note_foreach() callback signature easier to cope with from a binding perspective

These are deprecated and replaced with the diffing code in git2/diff.h

really reset walker with git_revwalk_reset

Update git_status_file and add ranged iterators

A few indexer consistency checks

This function fills in a git_buf with the common prefix of
an array of strings, but let's make that a little more clear.

Error out in finalize if there is junk after the packfile hash or we
couldn't process all the objects.

The goal of this work is to rewrite git_status_file to use the
same underlying code as git_status_foreach.

This is done in 3 phases:

1. Extend iterators to allow ranged iteration with start and
   end prefixes for the range of file names to be covered.
2. Improve diff so that when there is a pathspec and there is
   a common non-wildcard prefix of the pathspec, it will use
   ranged iterators to minimize excess iteration.
3. Rewrite git_status_file to call git_status_foreach_ext
   with a pathspec that covers just the one file being checked.

Since ranged iterators underlie the status & diff implementation,
this is actually fairly efficient.  The workdir iterator does
end up loading the contents of all the directories down to the
single file, which should ideally be avoided, but it is pretty
good.

From the description  of git_revwalk_reset in revwalk.h the function should
clear all pushed and hidden commits, and leave the walker in a blank state (just like at creation).
Apparently everything gets reseted appart of pushed commits (walk->one and walk->twos)

This fix should reset the walker properly.

Fix compilation warnings

Add git_note_foreach()

This reverts commit 1093e2de.