Moved platform detection

Summary:
- Move platform detection to a different directory
- Abstracted some interface methods to IDetection
- Added IBrowserDetection interface
- Added IOperatingSystemDetection interface
- Updated Facade

Test Plan: Ran unit tests

Reviewers: brooke, rgooding, JayFrancis

Reviewed By: rgooding

Differential Revision: http://phabricator.cubex.io/D34