add a section for pillowtop on the admin system dashboard

depends on https://github.com/dimagi/pillowtop/pull/45
![screen shot 2013-09-22 at 10 06 35 pm](https://f.cloud.github.com/assets/137212/1188941/519e2e7e-23f6-11e3-8d8e-71e35fd434ed.png)