Add .vundles.local to allow per-installation plugin customization

Adding and removing vim plugins is now done by adding and removing
from ~/.vim/.vundles.local. This file is sourced at the end of
vundles.vim

Fixes #275
Switching from Ack to Ag
Adding hack to make git completion faster for local stuff
Merge pull request #313 from lfilho/faster-git-compl

Adding hack to make git completion faster for local stuff
Merge pull request #303 from lfilho/ack2ag

Switching from Ack to Ag
Merge pull request #292 from skwp/vundles_local

Add .vundles.local to allow per-installation plugin customization
Merge remote-tracking branch 'upstream/master' into customizations

* upstream/master:
  Adding hack to make git completion faster for local stuff
  Switching from Ack to Ag
  Add .vundles.local to allow per-installation plugin customization