CocoaPods and build.sh updates

- Updated podspec to support both iOS & OSX
- `clean` now removes all non git-versioned files (except `core/`)
- added `browser` target
- added `deploy` target
- added `pod-deploy` target
How should it be separated? Should `prepare-deploy` save a marker file on success that `deploy` would check for, while any other build.sh command would delete? If we can't automate the required tests in between `prepare-deploy` and `deploy`, then those manual steps should be thoroughly detailed.