testing video scaling, fixed initial draw width & height destination
corrected backbuffer canvas sizing.
removed double variable assignement in the `me.Rect` constructor
improved the collision test example

makes it easier to see the performance improvement on the long run, and
easier to visualize the quadtree implementation
fixed the debugPanel `drawMemoryGraph` function

this is still broken though, as the memory usage stat are not being
displayed...
Fixed the debug Panel velocity drawing

same issue that with the memory graph earlier :P
renamed functions to make them clearer. Added docs to canvas renderer init
fixed debug panel
fixed debugPanel too :)
More fixes to the debugPanel following the API changes in the video renderer
Fixed body bounds update when setting/changing the default collision shape
Fixed an issue where the the game world container size was not updated after loading a TMX level
[#544] fixed wrong parameter order for the quadTree constructor
[#544] subscribes on the `LEVEL_LOADED` event to adjust the quadtree size based on the current game world size
[#544] new faster (and working) quadtree implementation based on Tino Hausmann library

this one can also be swapped with his spatial hash algorithm as they
both share the same API :)
[#544] QuadTree is now working and enabled by default !
[#544] couple of optimization to lower the creation of temporary variables
Merge remote-tracking branch 'upstream/master'