Fixed error: time not stopping when pausing the engine
Minor documentation change in Sprite class
Engine option added: defaultCollisionResolution (for setting the default collision checking resolution)
Collision objects now use the default resolution by default, but the resolution can be set on object level
The main canvas is now not user-selectable by browsers which supports it
A new example has been added for checking the effeciancy of collision checking (CollisionStressTest)
Collision checking refactored and simplified:
 - Non-rotatable bounding boxes can no longer be used
 - collidesWith has been divided into collidesWith and maskCollidesWith
 - collidesWith now has more simple options
Lots of improvements, and a few fundamental changes:
 - View→remove has been deleted (use engine.purge instead).
 - All views now has a default position of 0, 0.
 - All objects are now drawn relative to their parent view.
 - Custom loops has been refactored - a couple of bugs has been fixed.
	- The argument orders for schedule and the unschedule functions are now consistent with attach and detach functions.
	- It is now required to set a caller for scheduled functions (so that they can ALWAYS be easily unscheduled).
	- Using a scheduled function for scheduling or unscheduling other functions in the same loop, is no longer faulty
	- Scheduling now has a queue which is emptied after each frame (part of the fix for the above error)