Updated libgit2 to v0.19.0 tag
Merged updated test suite
Fixed GitOid to work directly with pygit2
Fixed Repository.target
Fixed blob tests
Added missing symbols
I don't understand the cause of this failure. Marking as expected to
differentiate from from skips due to unimplemented functionality
Skip tests for new unimplemented functionality
Fixed python 3 compatibility
Merge pull request #16 from sjagoe/upgrade-libgit2

Upgrade libgit2 and pygit2 test suite to 0.19.0