Refactored Reachability with a three-letter prefix

I refactored the Reachability class to have a three-letter prefix as per Apple's recommendations. http://developer.apple.com/library/ios/#documentation/cocoa/conceptual/ProgrammingWithObjectiveC/Conventions/Conventions.html

Great work on this class, thanks for providing it!

best,
Michael Fey
michael@nothirst.com
No Thirst Software LLC