@orta => Reserve-handling

Fixes #315.

/cc @katarinabatina 

![ios simulator screen shot nov 21 2014 6 18 42 pm](https://cloud.githubusercontent.com/assets/498212/5151434/f42c8b46-71ab-11e4-9070-ef25ac702858.png)

![ios simulator screen shot nov 21 2014 6 25 49 pm](https://cloud.githubusercontent.com/assets/498212/5151436/f690baec-71ab-11e4-8a83-332f19a31ff3.png)

Couldn't figure out how to make the init`(rawValue:)` initializer non-bailable.