Merge pull request #216 from nwidger/master

Added new `projectile-commander` methods ?v and ?R which run  `projectile-vc-dir` and `projectile-regenerate-tags`
[Fix #221] Add ack and ag to the commander
Modified `projecile-ack` to append options to `ack-and-a-half-arguments`
instead of overriding them.
Merge remote-tracking branch 'refs/remotes/upstream/master'

* projectile.el: merging upstream