Squashed commit of the following:

commit 3925205be35412aa48bab72094ccc43deac6b005
Author: Flurin Rindisbacher <info@flurischt.ch>
Date:   Sun Jan 6 14:57:04 2013 +0100

    dont step back when calculating the edgePoint

commit 973a1edf210afbf8ae5a16869fbcaed13d99f5fd
Author: Flurin Rindisbacher <info@flurischt.ch>
Date:   Sun Jan 6 14:31:35 2013 +0100

    for each edge point, dearch in rays in the other directory. use +/- 50 degrees around the incoming angle

    this way we can "move around" the glints.

commit d97b556347c6ca6562610eb7fdad867b96240ae6
Author: Flurin Rindisbacher <info@flurischt.ch>
Date:   Sun Jan 6 13:02:15 2013 +0100

    extract the edge extraction into its own method
use QMetaObject to invoke methods in the threads
Merge branch 'master' of github.com:Krigu/Gaze

Conflicts:
	GazeBrowser/threads/tracking/TrackingThread.hpp
add a possibility to stop the tracking via callback->imageProcessed()
only sleep on OSX when processing a frame
enable the real calibration
add another sleep for osx
prepare the tracke for a real world test
rename threads to workers