User can select provisioning profile when deploying via testflight

- add a Gemfile to point at gemspec
- back-fill testing for IPA generation
- slightly modify ThrustConfig to be more testable
- Lock to ruby 1.8.7, for compatibility with default Lionish OSX Rubies
- raise exception if provisioning profile not found
Merge pull request #13 from camelpunch/master

User can select provisioning profile when deploying via testflight