Add TreeDefinition.Add(string, TreeEntry)
Add rewrite test that injects existing TreeEntry
Fix building with Mono on OS X
Fix broken tests on OS X
Extension methods for NoteCollection using user from config

Similar to Repository.Commit, NoteCollectionExtensions.Add/Remove take the committer and author signature from the global git config user.name / user.email. This allows modifying notes without specifying the commiter explicitly
First stab at blame marshalling
Spike Repository.Blame
Fix marshalling structures
Avoid stealing ownership of signatures
Hunk by-line accessors
Another marshalling test
Don't use nested classes
Satisfy MetaFixture
Dispose of native blame handle asap
Newlines at end of new files
Expose Blame on IRepository
Move blame flag mapping to extension method
Use LaxUtf8Marshaler
BlameStrategy.Normal -> Default
Ifs should have braces