Add three admin scripts related to deactivation

final-gift.py is based on:
    https://gist.github.com/whit537/ec82f7d908b530336380

untip.py is based on:
    https://gist.github.com/whit537/b876265226c27c258dd0

deactivate-final-rename.py is based on
https://github.com/gittip/www.gittip.com/issues/54?source=cc#issuecomment-29240281
Merge pull request #1979 from gittip/add-scripts

Add three admin scripts related to deactivation