Documentation: Ignore some private methods.
Documentation fixes in both renderers

- Also fix the CanvasRenderer.strokeArc() implementation (matching fillArc)
[#594] fixed `me.Body` documentation
Update CHANGELOG

- Forgot about this!
- Also updated the Upgrade Guide with this note
minor fixes to debug panel. Still broken. Implemented basic stroke rect
somehow cleaned up the `me.Matrix3d` implementation a bit, and added a basic test suite for it
added empty missing functions to the webGL renderer so that the debug panel at least stop crashing when enabled
added missing matrix3d unit test in index.html
removed "draw" function all shapes objects and "moved" them to the renderer
Major version bump: 2.0.0
WebGL: Fix strokeLine()
Fix debugPanel color
[#598] Fix Array.prototype.random() and friends

- Also allow the [min] argument to be optional for Number.prototype.random() and friends
- Include updated documentation for the random functions
- Use the new shorter syntax everywhere, and fix some bugs along the way...
Fix renderer.drawShape with Ellipses
Fixed Ellipse (as opposed to circle) drawing with the canvas renderer
added missing `scale` function to the ellipse shape

Still missing rotation :P
simplified `me.Rect` furthermore, as these functions/properties are not used anymore
documentation : fixed parameters description for `me.CollectableEntity`

I'm wondering if this is still useful to keep this class ?
[#579] Howler 2.0

first commit !
[#579] fixed audio track resume