imports sorted

Signed-off-by: Felix Gabel <felix.gabel@me.com>
UIView category added

Signed-off-by: Felix Gabel <felix.gabel@me.com>
UIView category header added to XUIButton

Signed-off-by: Felix Gabel <felix.gabel@me.com>
innerCenter added to UIView

Signed-off-by: Felix Gabel <felix.gabel@me.com>