Added Calendar next/pre month links

fixes #726 
SS below - 
![calinks](https://cloud.githubusercontent.com/assets/1424236/4935484/78d712ae-65ad-11e4-99cc-dceb75400329.png)

I'm not sure if we should have hard-coded RGB values for these.

@chrismorast Are we exposing "theme-friendly" colors to use for links and backgrounds?