add jsbridge for debug purpose
HLSProvider/OSMF : implement DynamicStreamTrait to allow users to control dynamic bitrate switching.
it is working fine with GrindPlayer
there are still some issues with StrobeMediaPlayback, which is reporting a ReferenceError: Error #1069: Property 0 not found on builtin.as$0.MethodClosure when switching event is sent.

=> DynamicStreamTrait is conditionally compiled and only available in HLSProviderOSMFDynamicSwitching.swf
add a GrindPlayer sample test page

fix https://github.com/mangui/HLSprovider/issues/38