Support author_time
Fix tests: object_index() raises an exception now.
Support author/committer timezones.
Use new class name in __repr__ for child classes.
Pass lookup function into tree_lookup_path rather than dictionary-like object.
The parsing code is significantly different from the original in git now.
Support packed refs.
Remove mmap offset parameter use for now, as it appears to be broken and I have no good way to test it.
Split out tree parsing function.
Build extensions in Makefile.
Store tree contents in dictionary internally.
Improve formatting.
Fix skipping bug in index.
Add extra index test.
fix writing of legacy objects.
Fix padding in index.
allow changing the trees.
Fix syntax error in iteritems.
Fix index tests.
Don't close file twice.