Initial implementation of bencode/bdecode pod

Sorry about the length—at least half of the lines are the `xcodeproj` files, but there are still several hundred lines of implementation and several hundred lines of tests.

@vokalinteractive/ios-developers Anyone want to review some code?  (Log any time to `VOKMockUrlProtocol`.)
Bill Bumgarner (who works at Apple on the runtime and other low-level stuff) answered a Stackoverflow question about exceptions. His answer is the second-best ranked response:
http://stackoverflow.com/a/4649224/734466
He also linked to an older question: http://stackoverflow.com/questions/4648952/objective-c-exceptions

In short:
Exceptions in don't work well where resources aren't automatically managed. In Objective-C you should only use exceptions to indicate non-recoverable programmer error.