Support bypassing Host check

An empty $httpHost can be passed to circumvent checking Host header.
Merge branch 'refs/heads/clue-httphost'
Reverted the changes previously made in favor of a different approach as requested in https://github.com/cboden/Ratchet/pull/188
Added the property socket to the IOServer class and exposed the app and socket properties through getters.
Added a method to clear the allowedAccess array.
Merge branch 'github-master'
Added a method to expose the flashsocket
Merge branch 'flash-policy-fix'