Writing Clay tests for libgit2

For information on the Clay testing framework and a detailed introduction please visit:

https://github.com/tanoku/clay

• Write your modules and tests. Use good, meaningful names.

• Mix the tests:

    ./clay -vtap .
  

• Make sure you actually build the tests by setting:

    BUILD_CLAY=ON
  

• Test:

    ./build/libgit2_clay
  

• Make sure everything is fine.

• Send your pull request. That's it.