Improve Application Status report

fixes http://manage.dimagi.com/default.asp?111552
(https://github.com/dimagi/commcare-hq/issues/3345)

- improve accuracy and availability of version number
  - now checking `build_id` first, which was will only be in forms from apps built in the last month or so
  - added another pattern to check for in appversion text
- improve display of version number in report
  - nice html labels
  - explicitly say where it comes from in the hover (not very discoverable and only useful for advanced users)

![screen shot 2014-05-30 at 2 33 01 pm](https://cloud.githubusercontent.com/assets/137212/3134681/ff9116bc-e828-11e3-8f7d-dae85aa26cdd.png)