[#538] First commit with world collision shape support
[documentation] fixed the object scope
Simplified the slope shape

it seems there is some bug in the collision solving with complex
polygons, fixing it like this for now by simplifying the shape
[#538] clear the falling/jumping flag when required

do we keep these two one ?
[#538] converted the second level, and tweaked the first one a bit
[#538] removed the previous tile collision implementation

huge cleaning !
[#538] calculate residual velocity instead of nullifying it

this fixes movements/walking on slopes (or non rectangular shapes)
[538] optimized code, added variable shortcut to avoid "retraversing" the response object again and again
[documentation] fixed the getShape function return type, as it can never return a me.Rect object
[#568] fixed ResponseObject hidden class changes
Merge remote-tracking branch 'origin/1.1.x'
[#568] ResponseObject hidden class changes - part 2

this time with the old properties for backward compatiblity
Merge remote-tracking branch 'origin/1.1.x'
[#568] removed old properties from 1.1.0 (new API must be used now)
[#568] fix the onCollision handler, and use the last response API
[#569] clarified documentation on the requirement for polygons to be convex (for the SAT algorithm to work properly)
Merge remote-tracking branch 'origin/1.1.x'
[#538] first pass at the collision angle addition (not finished)

NOT WORKING, but that's all I will be able to do for today, so I prefer
to commit it as it for now.
[#538] further update to the collision angle
[#538] almost working collisionAngle

also fixed the `angleTo` and `angleToPoint` functions