Added option for 180 degree rotation. Settings part.

This patch enables the rotation to 180 degrees.
Inspired by a patch for cm61, where you could
toggle 90/180/270 degrees rotation.
Since WindowOrientationListener.java got completly
changed, i couldnt port that patch, but had
to implement it in a different way.

Change-Id: Iba1a323bf5058d5392fc287593cbd367561cfb73