Trebuchet: Add some padding to overflow icon in transition settings

Right now it's too close to the edge of the screen

Before: http://i.imgur.com/BjMXkvD.png
After: http://i.imgur.com/hTCcKuR.png

Change-Id: Id0aee703a9b34178480558f7daea2d4580660b70
Merge pull request #3 from CyanogenMod/cm-11.0

Trebuchet: Add some padding to overflow icon in transition settings