Support for Rubymotion

Huge fan of this excellent cocoapod! I've been using it with Rubymotion but since version 0.6 it mysteriously stopped working. 

Some further investigation shows that the NSDictionary that Rubymotion creates from hashes doesn't seem to gel well with `indexOfObjectIdenticalTo`, perhaps something to do with the way constants are handled? This change allows CRToast to be used with Rubymotion while keeping the valid key checking intact, hoping this is an acceptable compromise?