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
I don't think this is a good idea. The website lives in its own repo, including the docs, so this should be committed into the website repo instead. We need to be able to re-deploy the website very quickly and in a repeatable way in case anything goes wrong.