Fix SlidingPaneLayout padding

When measuring the children width take into account the layout
horizontal padding.

When reporting the layout measured height, take into account the
vertical padding that was removed to measure the children.

And when sliding the pane, make sure views are not offset vertically.

Change-Id: If17912b94fa6721c199ad1a050d8c7350738076b
Signed-off-by: Sérgio Faria <sergio91pt@gmail.com>
Fragement, or Fragment: that is the question

Change-Id: I6fde7683cb83eecf96380d38fc588679d1ed1002