Add git aliases for git qa and git qa-tidy

Adding default git aliases for git qa and git qa-tidy
Example usage:
git qa 12344
git qa-tidy 12344

What they do:
git qa bugnumber
Checks out master
Fetches origin/master
rebases origin/master
Checks out a branch: qa-bugnumber based on master
Fetches the patches from bug bugnumber from bugzilla and attempts to apply them.

git qa-tidy bugnumber
checks out master
deletes the qa branch associated with bugnumber