Disable garbage collection of cross-references to prevent
double-freeing. Internal reference management is now done
with a separate method.

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

All `git_object` instances looked up from the repository are reference
counted. User is expected to use the new `git_object_close` when an
object is no longer needed to force freeing it.

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

The methods previously known as

	git_repository_lookup
	git_repository_newobject
	git_repository_lookup_ref

are now part of their respective namespaces:

	git_object_lookup
	git_object_new
	git_reference_lookup

This makes the API more consistent with the new references API.

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

The new signature struct is public, and contains information about the
timezone offset. Must be free'd manually by the user.

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

Libgit2 is now officially include as

	#include "<git2.h>"

or indidividual files may be included as

	#include <git2/index.h>

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

The maze with include dependencies has been fixed.
There is now a global include:

	#include <git.h>

The git_odb_backend API has been exposed.

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

Comes with two default backends: loose object and packfiles.

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

Replaced magic number "0" with GIT_SUCCESS constant wherever it made sense.

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

All initialization functions now return error codes instead of pointers.
Error codes are now properly propagated on most functions. Several new
and more specific error codes have been added in common.h

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

String mememory is now managed in a much more sane manner.

Fixes include:

	- git_person email and name is no longer limited to 64 characters
	- git_tree_entry filename is no longer limited to 255 characters
	- raw objects are properly opened & closed the minimum amount of
	times required for parsing
	- unit tests no longer leak
	- removed 5 other misc memory leaks as reported by Valgrind
	- tree writeback no longer segfaults on rare ocassions

The git_person struct is no longer public. It is now managed by the
library, and getter methods are in place to access its internal
attributes.

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

Tag files can now be created and modified in-memory (all the setter
methods have been implemented), and written back to disk using the
generic git_object_write() method.

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

All repository objects can now be created from scratch in memory using
either the git_object_new() method, or the corresponding git_XXX_new()
for each object.

So far, only git_commits can be written back to disk once created in
memory.

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

The 'git_obj' structure is now called 'git_rawobj', since
it represents a raw object read from the ODB.

The 'git_repository_object' structure is now called 'git_object',
since it's the base object class for all objects.

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

git_repository_object has now several internal methods to write back the
object information in the repository.

- git_repository__dbo_prepare_write()
	Prepares the DBO object to be modified

- git_repository__dbo_write()
	Writes new bytes to the DBO object

- git_repository__dbo_writeback()
	Writes back the changes to the repository

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

All loaded objects through git_repository_lookup are properly parsed &
free'd on failure.

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

The old 'git_revpool' object has been removed and
split into two distinct objects with separate
functionality, in order to have separate methods for
object management and object walking.

*	A new object 'git_repository' does the high-level
	management of a repository's objects (commits, trees,
	tags, etc) on top of a 'git_odb'.

	Eventually, it will also manage other repository
	attributes (e.g. tag resolution, references, etc).

	See: src/git/repository.h

*	A new external method
		'git_repository_lookup(repo, oid, type)'
	has been added to the 'git_repository' API.

	All object lookups (git_XXX_lookup()) are now
	wrappers to this method, and duplicated code
	has been removed. The method does automatic type
	checking and returns a generic 'git_revpool_object'
	that can be cast to any specific object.

	See: src/git/repository.h

*	The external methods for object parsing of repository
	objects (git_XXX_parse()) have been removed.

	Loading objects from the repository is now managed
	through the 'lookup' functions. These objects are
	loaded with minimal information, and the relevant
	parsing is done automatically when the user requests
	any of the parsed attributes through accessor methods.

	An attribute has been added to 'git_repository' in
	order to force the parsing of all the repository objects
	immediately after lookup.

	See: src/git/commit.h
	See: src/git/tag.h
	See: src/git/tree.h

*	The previous walking functionality of the revpool
	is now found in 'git_revwalk', which does the actual
	revision walking on a repository; the attributes
	when walking through commits in a database have been
	decoupled from the actual commit objects.
	This increases performance when accessing commits
	during the walk and allows to have several
	'git_revwalk' instances working at the same time on
	top of the same repository, without having to load
	commits in memory several times.

	See: src/git/revwalk.h

*	The old 'git_revpool_table' has been renamed to
	'git_hashtable' and now works as a generic hashtable
	with support for any kind of object and custom hash
	functions.

	See: src/hashtable.h

*	All the relevant unit tests have been updated, renamed
	and grouped accordingly.

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

Tag objects are now properly loaded from the revision pool.
New test t0801 checks for loading a parsing a series of tags, including
the tag of a tag.

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