pygit2 v0.17.3 released

This should be the last release in the v0.17 series. The master branch has already been moved to be based in the libgit2’s development branch.

New in v0.17.3:

• New Blob.size getter
• New Repository.create_blob_fromfile method
• Signature, now the time and offset parameters are optional
• Improved diff support
• Add pygit2.__version__
• Optimize usage of Travis
• Various fixes for the unit tests
• Various documentation improvements

Thanks to Alex Chamberlain, Carlos Martín Nieto, Eric Davis, Eric Schrijver, Petr Viktorin, Ridge Kennedy and W. Trevor King.