Quick add transactions

Added a small bar at the bottom of the overview page to quickly add Expenses, Incomes and Transfers.
Just an idea at the moment and icons are more like placeholders than actual resources.

Also set navigation bar background to match Primary Color

![quick_add_bar](https://cloud.githubusercontent.com/assets/8081613/3629725/cfa11c80-0ea3-11e4-9dc5-9da8e28d932a.png)