As flipping can be considered as a way to "rotate" things, it makes sense to have it used as a center for flipping too.i
This is useful for objects that are moving and can be flipped according to if they are going left or right: they can now
be rotated and flipped "properly" (properly means that the center will stay at the same position when flipped/rotated)
This means that the center point won't move when the sprite is rotated or flipped.
The origin is still used as the point not moving in case of scaling. (this make sense because scaling is about the size, and origin about positioning)
This remove some calculations in the renderers, but add others in getDrawableX/Y and getCenterX/Y in case of flipping.
* "Bug" is fixed by ignoring edges when doing collision tests for
the platform engine.
* Also add an option to round coordinates and ensure pixel-perfect
alignement of characters on platforms (on by default)
* Also add an optional parameter to ignore edges when
doing a collision test (or when separating objects)
Garett Tok Ern Liang