Win32 DLLs have four fields for the version number (major, minor,
teeny, patch).  If a consumer wants to build a custom DLL, it may
be useful to set the patchlevel version number in the DLL.

This value only affects the DLL version number, it does not affect
the resultant "version number", which remains major.minor.teeny.

Bump the version number to 0.22.0 and the SOVERSION to 22.

Bump library version to 0.21.0 and SONAME to 21

Since the SOVERSION doesn't need to follow the library's version and
simply needs to be monotonically increasing whenever we release
something that breaks the ABI, we can set some number and allow multiple
versions of the library to be installed side-by-side.

We start here with the minor version as that's what we release for now,
and it allows to backport this change to earlier versions.

Apologies for the delay. This release is chunky,
but you're probably used to chunky releases by now.

Full changelog follows:

Internal changes
	+ Added support for decomposed Unicode paths in Mac OS X
	+ Added support for junctions in win32
	+ Fixed issues with HTTP redirects in the network stack
	+ Performance improvements (as always)

git2/blame.h
	+ added full support for blame operations

git2/blob.h
	+ added `git_blob_filtered_content` to load blobs in
	memory with their corresponding filters applied

git2/branch.h
	+ added branch iterators as an alternative to the
	callback-based API

git2/buffer.h
	+ exported the git_buf struct to allow binary buffers
	to be passed from/to the library. This simplifies
	several APIs

git2/checkout.h
	+ implemented additional checkout options ('skip unmerged',
	'use ours' and 'use theirs')

git2/clone.h
	+ simplified the clone API
	+ added new `git_clone_into` to clone into an existing
	(empty) repository

git2/commit.h
	+ added APIs to access the raw (uncleaned) text of a commit
	message

git2/common.h
	+ added global options to set the default paths to load
	templates from

git2/config.h
	+ added multivar iterators
	+ added globbing iterator
	+ added `git_config_foreach_match` to perform operations
	on every single var in a config file

git2/diff.h
	+ restructured and simplified the diff API

git2/filter.h
	+ added external APIs to configure and apply custom filters
	to checked out blobs

git2/index.h
	+ `git_index_read` can now force a reload of the index file
	even if it hasn't changed on-disk

git2/indexer.h
	+ improved the streaming indexer APIs

git2/merge.h
	+ added support for merge!

git2/object.h
	+ added helper API to lookup a generic object by path

git2/pack.h
	+ added progress callbacks to the packbuilder

git2/patch.h
	+ added support for patch generation as part of the Diff
	API revamp

git2/pathspec.h
	+ added helper APIs to work with pathspecs and match files
	in the workdir or diffs

git2/push.h
	+ added progress callbacks to push

git2/reflog.h
	+ changed reflog APIs to work on reference names instead of
	the references themselves, so they become less racy

git2/remote.h
	+ added support for setting refspecs on remotes, either at
	creation or on existing ones
	+ simplified the remotes API

git2/revwalk.h
	+ add API to simplify parents during a walk

git2/signature.h
	+ add helper to create a signature with the default values for
	a repository (i.e. the set `user.name` and `user.email` values,
	and the current time)

git2/submodules.h
	+ improve the status detection for submodules

git2/sys/
	+ exported many new internal APIs, such as pluggabe transport
	APIs

-vmg, out