Update http_parser.rb dep to 0.6.0.pre2

em-http-request needs to be updated to 1.1.1 for dependency compatibility

em-websocket-client added to spec suite since em-http-request 1.x does not support websockets

Only functional change outside of this was to manually parse the request_path and query_string as those are no longer exposed by the http_parser C library [1]. This could be reworked a bit to store the URI instance or other if this functionality is still needed.

If anything else needs to be done to clean this up to be able to make it in just shout out.

Thanks.