Added new transform property to cpSpaceDebugDrawOptions

[viblo]

This PR adds a transform property to cpSpaceDebugDrawOptions, and the transform is applied on the drawing of shapes. However, it is not applied to the size of the dot when drawing constraints. In this way you can make a scaling transform and zoom in without the constraint dots filling up the screen hiding everything else.

This is also the reason why this change has to be done in cpSpaceDebug, since if I just do the transform inside the draw functions (dot, segment, fat segment etc) drawing of DampedSpring will not work nicely. (This is what I tried first)

Code can most likely be optimized further, Im open to suggestions.

[slembcke]

This is already handled using the ChipmunkDebugDrawPointLineScale global constant. Is it possible to just use that instead?

[viblo]

It was a while since I looked at this, but I think in addition to the point sizes also the spring (the zigzag part) didnt scale properly.