Updated the "gpp" alias and added the "gpr" and "gps" aliases.

* All three of these aliases use a "production", "stage", and "review"
  Git remote (see .git/config per project).
* The "gpp" changed to use the "production" instead of "master" branch.
* The "gpr" uses the "master" branch to push to the "review" remote.
* The "gps" uses the "stage" branch to push to the "stage" remote.