use 'open' program in different system

in MAC OSX using open
in LINUX   using xdg-open
in WINDOWS using start

Signed-off-by: xiehuc <xiehuc@gmail.com>
destroy chat dialog when delete friends

在删除好友之后查找当前打开的聊天对话框,因为该对话已经无效了.所以需要关闭
该对话框

Signed-off-by: xiehuc <xiehuc@gmail.com>
fix in adium write twice sended message

Signed-off-by: xiehuc <xiehuc@gmail.com>