Make JSC buildable as a referenced project
Add the new Objective C API headers to the other Public headers
Expose ArrayBuffers through the Objective C JSValue API
Dirty workaround for when running on iOS 7 and JavaScriptCore.framework is already loaded.

UIKit begets WebKit, WebKit begets JavaScriptCore and that tries to
register the same Objective C classes as the statically compiled JSC.
Merriment ensues.