handle_frame: pull up DATA_FRAMING_CLOSE
handle_frame: pull up DATA_FRAMING_CLOSE

The strange "call handle_frame() once more after close to do nothing"
case mentioned in the last commit is now removed; DATA_FRAMING_CLOSE is
now handled directly by handle_incoming(), and handle_frame() returns
zero if it wants the connection to close.

jchampio/apache-websocket,jchampio/apache-websocket,jchampio/apache-websocket