Use correct prototypes
return NULL over -1
Merge remote-tracking branch 'richo/bugs/compiler_warnings'
Make Repostirory_as_iter shorter

Error_set already returns NULL
Readme: add table of contents
sphinx-quickstart
Use autodocs
Copy docs from the readme file
Simplify README file
Update authors list

And remove AUTHORS text file.
docs: split usage guide into several source files
Update to latest libgit2 API renaming

See libgit2 commit 25743bd7c5f14f2287d9c4, where git_index_add_from_workdir
was renamed to git_index_add_bypath
docs: make autodoc work without installing pygit2
docs: merge auto generated and hand writen docs
Improve Index docs

And fix a refcount error through the way.
docs: working on the repository chapter (in progress)
docs: working on the repository chapter (continue)
fixed api changes for index.c

11d9f6b304 in libgit2 changed api for git_index_find()
variable renaming
added GIT_EINVALIDSPEC as error code and use error msg for expected failures