fix priority and title display in cards lists

Fixes
-------
- display card-short-id at the beginning of the card title, without adding the id to the title
- display priority for a card if set. If not set, do not display ( e.g. example card #798 below)

![screen shot 2014-02-24 at 4 13 08 pm](https://f.cloud.github.com/assets/831105/2252897/baa555c0-9db1-11e3-8472-6a957e0a7315.png)