Vim: Remove AfterColors plugin
Vim: Remove AnsiEsc plugin
Vim: Remove csapprox plugin
Vim: Remove relative numbering and the ability to toggle it on/off

Remove:
 * Ability to toggle relative numbering
 * Initial setting of relative numbering
Vim: Add ack.vim plugin (using ag)

Add:
 * ack.vim plugin
 * The use of ag (the_silver_searcher) when using ack