Code optimization.

fix swoole_server unix dgram length error.

fix bug: set max_coro_num doesn't work

update packege.xml

fix swoole_event callback invalid.

Merge branch 'hantianfeng'

Merge branch 'hantianfeng'

update package.xml

fix swoole_websocket_server->exist cannot use when client accept from…

… un-websocket listen port.

add --enable-thread option.