Two minor optimizations in heavily used code paths.
Release 0.9.4.
Start on 0.9.5.
Move refs tests to dulwich.tests.test_refs.
Remove compatibility code for collections.defaultdict, in preparation of
dropping support for Python < 2.6.
Remove compatibility code for itertools.permutations, in preparation of
dropping Python2.4 and 2.5 support.
Drop compatibility replacement for unpack_from.
Drop compatibility replacement for 'all'.
Drop compatibility function for namedtuple.
Drop compatibility functions for `hashlib.sha1`.
Drop compatibility wrapper for `parse_qs`.
Drop compatibility wrapper for `SEEK_END` and `SEEK_CUR`.
Update NEWS.
Update README, add link to homepage.
Fix description for pypi.
Line wrap.
Add explanation of porcelain and plumbing terms.
Remove some long deprecated methods on Repo.
Remove long deprecated Repo.ref and Repo.revision_history.
Remove long deprecated Tree.entries.