More or less a total rewrite.
But visible changes are:
- Improved transition animation when moving to/from preview
- Replaced select/deselect button title in preview with the checkmark view instead (no need for localization :))
- Removed "Back" from the back button
![out](https://cloud.githubusercontent.com/assets/4034956/3212805/680b1e88-ef75-11e3-9410-a5de4b4f92d2.gif)