Add ag Vim plugin

A.k.a. The Silver Searcher
Remove ack in favor of ag

Reverts fc5e37f52b008781fbdf5c1e7569d2d9fa89273b
Update submodules

'git submodule foreach git pull origin master' is my new best friend
Update Pathogen commands in .vimrc

Based off recommendation in update from previous commit
Add git submodule update loop

NICE
Separate Homebrew formulae into lines

Easier to maintain and read this way.