Added option for 180 degree rotation.

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: If3c7240ac72c8a7ebec02582fbaa3ef4933d52d9