Resize special items

I resized the images for special items so they'd all be the same size as the gems.

![screen shot 2014-12-30 at 12 04 32 pm](https://cloud.githubusercontent.com/assets/2916945/5581247/1b4c4ba6-901c-11e4-85a9-191e1676e861.png)

Spooky Sparkles and Snowballs have a separate image for when they appear in the rewards column, so the change does not affect them there.

The only other place one of the items appears is in the rebirth modals, which gives it just a hair more extra padding, which I like:

## Before
![screen shot 2014-12-30 at 12 09 40 pm](https://cloud.githubusercontent.com/assets/2916945/5581301/5600e74c-901d-11e4-89ab-9a8c956af376.png)

## After
![screen shot 2014-12-30 at 12 09 46 pm](https://cloud.githubusercontent.com/assets/2916945/5581303/5b13b5a2-901d-11e4-8e49-8d09733552cc.png)

## Before
![screen shot 2014-12-30 at 12 22 24 pm](https://cloud.githubusercontent.com/assets/2916945/5581365/922c9dd2-901e-11e4-963f-37f39e0c0dba.png)

## After
![screen shot 2014-12-30 at 12 15 54 pm](https://cloud.githubusercontent.com/assets/2916945/5581366/978a04a4-901e-11e4-9307-257e4778370e.png)