Features:

- New 'Blob.size' getter
- New 'Repository.create_blob_fromfile' method
- Signature, now the time and offset parameters are optional
- Improved diff support

Other:

- 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.