add a icon for kuaipan4uk

kuaipan is a chinese cloud storage service. they released a client for
ubuntukylin

Signed-off-by: xiehuc <xiehuc@gmail.com>
remove kuaipan4uk's shadow

Signed-off-by: xiehuc <xiehuc@gmail.com>
fix round corner unbalance for right down rect

Signed-off-by: xiehuc <xiehuc@gmail.com>
Merge pull request #480 from xiehuc/master

add a icon for kuaipan4uk