add: first implement of updater.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
add: fork ability;
add: add entry point for updater.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
update: make keepAlive optional;
minor changes on updater.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
change: read changelog from files;
change: callback in socket.js;
doc: add language.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
add: error handler to every JSON operation.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>
fix: room info sometimes missing.

Signed-off-by: liuyanghejerry <liuyanghejerry@126.com>