envsetup: add more functions

groot: go to root of git project
pstest:  cherry pick a patch from the Nameless gerrit instance.
pspush:  push commit to Nameless gerrit instance.
addaosp:  Add git remote for the AOSP repository
addgerrit: Add git remote for the Nameless gerrit

Change-Id: Ie6e4fcee0e667997f882fdd97344e16d918a209a