add Lwqq::friends()

Signed-off-by: xiehuc <xiehuc@gmail.com>
add get friend qqnumber and detail info

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

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

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