fixed #2728, Moved geometry primitives out of src/core into src/math.  src/core is now exclusive scene primitives.

More garbage collection friendly Box2.distanceToPoint(), Box3.distanceToPoint() and Vector3.distanceToSquared()

Would be great if the function to get angle to anonther vector could be implemented in this Vector3 class.
Hope you guys like the idea.

(Phewww!) I'm sure there are still things I missed...

first update towards typedarray usage in matrices\n This was done with some simple replaces it doesn't work yet

This adds Vector3.getRotationFromQuaternion and changes Object3D.applyMatrix to use Matrix4.decompose.

Also added SceneUtils.attach / detach and cleaned up unused vector parameter in Geometry.applyMatrix.

Renamed Vector3.setRotationFromMatrix() to Vector3.getRotationFromMatrix().
Added Vector3.getScaleFromMatrix().

As usual, it's up to caller to cache the value if it's not used right away.

Had to use Matrix4's internal matrix to avoid circular cross-dependency between Vector3 and Matrix4 (added extra internal matrix m3 for this not used anywhere in Matrix4 itself to minimize chances of messing up something).

Added Vector3.absoluteToRelative and Vector3.relativeToAbsolute. Thanks to @G3z for the initial suggestion. Thanks to @em for the naming hint. Fixes #1043.

Also trying to make a bit nicer UVs for ExtrudeGeometry / TextGeometry.

Not sure about this hardcoded epsilon thing for "isZero", also related strict equality check. Maybe these should be configurable somehow.

Simplified `Trident`.
Added `setX`, `setY`, `setZ` methods to `Vector3`. They're handy for oneliners (see `CylinderGeometry`).

Some clean up on Vector* constructors.
Added UV::clone.