public void setArcRotation(int mRotation) {
		this.mRotation = mRotation;
		updateThumbPosition();
	}
Sets a listener to receive notifications of changes to the SeekArc's
progress level. Also provides notifications of when the user starts and
stops a touch gesture within the SeekArc.

@param l
           The seek bar notification listener

@see SeekArc.OnSeekBarChangeListener
SeekArc_library/src/com/triggertrap/seekarc/SeekArc.java