More Networking updates

This limitation was a misparsing of the documentation.

This allows the caller to update an internal structure or update the
user output with the tips that were updated.

While in the area, only try to update the ref if the value is
different from its old one.

In the case that walk->one is NULL, we know that we have no positive
references, so we already know that the revwalk is over.

This allows us to give updates on how it's doing

Trying to send every single line immediately won't give us any speed
improvement and duplicates the code we need for other transports. Make
the git transport use the same buffer functions as HTTP.

This changes the git_remote_download() API, but the existing one is
silly, so you don't get to complain.

The new API allows to know how much data has been downloaded, how many
objects we expect in total and how many we've processed.

Code clean up, including fixing warnings on Windows 64-bit build

Fix git_repository_set_odb() refcount issue

git_repository_free() calls git_odb_free() if the owned odb is not null.

According to the doc, when setting a new odb through git_repository_set_odb() the caller has to take care of releasing the odb by himself.

Signed-off-by: schu <schu-github@schulog.org>

The code used to assume that there had to be data after the newline in
a tree cache extension entry. This isn't true for a childless
invalidated entry if it's the last one, as there won't be any children
nor a hash to take up space.

Adapt the off-by-one comparison to also work in this case. Fixes #633.

Index refcount issue

This fixes all the warnings on win64 except those in deps, which
come from the regex code.

Adds a new public reference function `git_reference_lookup_oid`
that directly resolved a reference name to an OID without returning
the intermediate `git_reference` object (hence, no free needed).

Internally, this adds a `git_reference_lookup_resolved` function
that combines looking up and resolving a reference.  This allows
us to be more efficient with memory reallocation.

The existing `git_reference_lookup` and `git_reference_resolve`
are reimplmented on top of the new utility and a few places in the
code are changed to use one of the two new functions.

This updates to the latest clar which includes the helpers
`cl_assert_equal_s` and `cl_assert_equal_i`.  Convert the code
over to use those and remove the old libgit2-only helpers.

This removes the code for the old status implementation.

Support config value quoting

Variable values may be quoted to include newlines, literal quotes and
other characters. Add support for these and test it.

ifdef GIT_WIN32 helper unposix_path() to avoid unused-function warning
on non-Windows systems.

Signed-off-by: schu <schu-github@schulog.org>

git_repository_free() calls git_index_free() if the owned index is not null.

According to the doc, when setting a new index through git_repository_set_index() the caller has still to take care of releasing the index by itself.

In order to cope with this, this fix makes sure the index refcount is incremented when a new repository is being plugged a new index.

Removed unreferenced variables.

Diff with pathspec

This adds preliminary support for pathspecs to diff and status.
The implementation is not very optimized (it still looks at
every single file and evaluated the the pathspec match against
them), but it works.

Resolve any lingering deltas, write out the index file and rename the
packfile.

This will allow us to index a packfile as soon as we receive it from
the network as well as storing it with its final name so we don't need
to pass temporary file names around.

Update git_repository_open

The new indexer needs to be able to bypass any kind of buffering, as
it's trying to map data that it has just written to disk.

The cleanup needs to happen anyway, so set the error code and jump
there instead of copying the code.

Plug a few leaks