Minor deprecation and packaging improvements.

Compile and test fixes

Tagging version 0.50.4

Tagging v0.50.3

Tagging v0.50.2 containing some small fixes to 0.50.1

Tagging v0.50.1

Tagging v0.50.0 with an almost complete API and 0.19.0+0.20.0 support

Tagging v0.1.0

New bindings based on libgit2 0.20.0.

Tagging v0.19.0 - corresponds to libgit2 0.19.0.