Added Target for creating a static library

Integrating this framework in other projects is much easier if a static library is built. Especially if this NonARC-Project needs to be added to current ARC-Based project as mine.

Therefore, I've added a target for iOS.

An other very important change: Mostly all projects use the Reachability Classes. Therefore we get duplicated symbols here.. I've added a "_" prefix to mark it as private.