Introduce Blob.IsBinary
Provide access to basic username/password auth for clone
Remove ThreadAffinity from git_remote_set_autotag
Add test repository with merge conflicts
Add IndexContainsUnmergedEntriesException to bind EUNMERGED exception
Bind git_graph_ahead_behind native method

Replace current implementation of Branch.AheadBy and Branch.BehindBy with git_graph_ahead_behind call
Add Ignore support

This PR adds support for the new .gitignore methods in libgit2
Re-enable skipped hard reset test
Update checkout in response to libgit2 checkout changes
Add checkout tests
Checkout branch as snapshot
Add TODO comment
Small documentation fix
Fix some compilation warnings
Enhance checkout test coverage
Introduce OrphanedHeadException
Update libgit2 binaries to 586f71e

https://github.com/libgit2/libgit2/compare/7dfc5c3...586f71e
Make Checkout raise proper MergeConflictException
Enhance Index.RetrieveStatus() test coverage

Partially fix git-tfs/git-tfs#231
Tidy up OdbBackendFixture code