Stats heatmap

Take a look and let me know what you think. Attached screenshots of the 4 contexts where the heat bars show up (years, tours, shows, show). I'm definitely open to changing stuff. I'm also not 100% sure years and tours need them, but it feels right with shows and show/tracks.


![ios simulator screen shot oct 18 2014 10 52 08 pm](https://cloud.githubusercontent.com/assets/120678/4692233/273ff1fc-5754-11e4-8fef-f7f76d3c86e2.png)
![ios simulator screen shot oct 18 2014 10 52 15 pm](https://cloud.githubusercontent.com/assets/120678/4692232/273d0c1c-5754-11e4-9c57-6323b54044fc.png)
![ios simulator screen shot oct 18 2014 10 52 18 pm](https://cloud.githubusercontent.com/assets/120678/4692234/27404e18-5754-11e4-8632-fd78c819c999.png)
![ios simulator screen shot oct 18 2014 10 52 32 pm](https://cloud.githubusercontent.com/assets/120678/4692235/274175c2-5754-11e4-8287-19dceec649ce.png)