fix send message msg_id autoincrement

把msg_id从lc移到了msglist中,并且在发送的时候自动加1.

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

use it when received group/discu message to get whether lost messages!!

Signed-off-by: xiehuc <xiehuc@gmail.com>
add auto increment seq for group message

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