Command-line completion for branches, remotes, ...

- New setting g:Git_BinPath, to set the path to the executables.
- Command-line completion for subcommands, branches, remotes, tags.
- :GitStatus can work with changes introduced by Git version 1.8.5.
- New maps for the branch and status buffers.
- Minor changes.
- Updated the documentation.

taken from WolfgangMehner/vim-plugins, revision
https://github.com/WolfgangMehner/vim-plugins/commit/6bac77cc6fb8105943af602e9abeab64c4cc30bf