Stats UX Improvements

I sought out to make the stats view load data more smoothly. The bar chart used to jerk when loading, and when you switched views the fragment would shrink before loading the new fragment which looked unpleasing. 

I used custom fragment transition animations to do a nice fade when you switch views. Before and after can be viewed here:

https://cloudup.com/iuwRdDJ0sDy

Fixes #310 and #221