upgrade vendors
[vim] remove ycm
[vim] configure with luajit
[vim] add neocomplete
[vim] remove ctrlp
[vim] configure unite with a couple plugins
[vim] fix unite settings
[vim] add sbt quickfix plugin
[vim] configure airline
[vim] install and configure gitgutter
[vim] install quickfixsigns
Revert "[vim] install and configure gitgutter"

This reverts commit d5cacc939f4a939ce7be184271c9f20ccce2e732.
Merge branch 'qf'

* qf:
  [vim] install quickfixsigns