Fixed project setup problems & ARC problems

[BlackWolf]

The project did not compile successfully on iOS 7 and iOS 8, which is fixed in this request. This includes removing dispatch_release, setting the deployment target to iOS 6 and some minor project setup issues.

IMPORTANT: I didn't test this with iOS 6 - if we want to keep iOS 5/6 compatibility this should NOT be merged. Technically, I don't see an issue why this code shouldn't work on earlier iOS versions (ARC is supported since iOS 4 if I'm not mistaken?), but its untested.