[plugin] Added vim-git and updated plugin list

- Added vim-git for git filetypes and highlight
- Updated plugin list that must be tested

Change-Id: If2bac92ae72bf8c27ec870fd68086a9118371219
[plugin] Cleanup and strutctuted plugin orgnization

Organized the NeoBlundle plugin list. Main feature is a new session for the
unite plugin

Change-Id: I8cdecce846c510b51012cc59a9286925378bd229