[modify] don't need to set "root" privilege in nginx conf file.
	modified:   nginx.conf
[modify] add some sqls to configure mysql for Quick_Server.
	modified:   base.sql
	new file:   pre_condition.sql
[modify] add "-p" option to avoid an error from "mkdir" if "user_codes" dir has already existed
	modified:   UserAction.lua
[modify] copy Quick-Server tools to /opt/quick_server.
	modified:   install_ubuntu.sh
[modify] this shell can receive an param to indicate installation path now.
	modified:   install_ubuntu.sh