Update playdoh-lib

91561d9 Update to Django 1.4.6  r=r1cky
198b178 Merge pull request #42 from dpoirier/update-tower
e8e6095 Update tower
77d2cc7 Merge pull request #36 from jsocol/arecibo
54be25a Merge pull request #40 from peterbe/upgrade-django-session-csrf
963f25c upgrade django-session-csrf for safer keys
d5db036 Drop django-arecibo.