Naive fix for PCL targetFramework selection

Fixes #511

Before:
![2014-04-01_09-43-36](https://cloud.githubusercontent.com/assets/582487/2576633/aca484a6-b971-11e3-8170-22e91de70893.png)

After:
![2014-04-01_09-32-13](https://cloud.githubusercontent.com/assets/582487/2576636/b34f4bec-b971-11e3-807c-fa58bf00858d.png)

This might be a bit naive, but it works:

![2014-04-01_09-58-43](https://cloud.githubusercontent.com/assets/582487/2576699/486dc996-b973-11e3-9d8e-f99b354af9d4.png)

:grin::+1: