Make deck description scrollable  (issue 1974)

**Note:**  This commit can wait for v2.2... it's low priority

It moves the deck description to the bottom of the deck info layout, and disables truncation of the deck description so that users can scroll to view the whole text. Solves [issue 1974](https://code.google.com/p/ankidroid/issues/detail?id=1974)

Unfortunately for very small screens, it may mean that scrolling is necessary to see *any* of the deck description, but for most screen-sizes it should not be a problem. See the below screenshot for an example of what I mean on QVGA (smallest Android screen size)

![scrollable description](https://f.cloud.github.com/assets/2818274/2470456/ffbf93f0-b012-11e3-8e71-da0b36e0b991.png)