Add Vim Tmux Navigator

This plugin is a repackaging of [Mislav Marohnić][1]'s
tmux-navigator configuration described in this
[gist][2].

When combined with a set of tmux key bindings,
the plugin will allow you to navigate seamlessly between vim and tmux splits
using a consistent set of hotkeys.

**NOTE: This requires tmux v1.8 or higher.**

[github.com/christoomey/vim-tmux-navigator][1]

[1]: http://mislav.uniqpath.com/
[2]: https://gist.github.com/mislav/5189704
[3]: https://github.com/christoomey/vim-tmux-navigator