Add GrepAdd command
Add LGrep command
Add LGrepAdd command
Refactor the plugin into autoload
Refactor some more
Refactor function names
Autoload grep module
Add module for ack

Add commands:
* Ack
* AckAdd
* LAck
* LAckAdd
Add module for ag (the_silver_searcher)

Add commands:
* Ag
* AgAdd
* LAg
* LAgAdd
Add master command G
Add G commands

G, GAdd, LG, LGAdd

These commands will try to use the fastest utility available, in this
order:

ag, ack, then grep
Force redraw of screen
Add mappings to the quickfix window
Refactor GreperUtility
Change function names