Matrix4.lookAt(): y doesn't need to be normalized because it's a cross product of 2 normalized vectors

Not sure it's really correct, it's kinda hard to tell.

Also made stress test more fancy and heavy. It's interesting how antialiasing increases performance difference for more complex materials.

Also some shaders refactoring.

Still todo: doubleSided handling for reflections / refractions.

As per discussion in #1324

This fixes geometry tessellation example (before TextGeometry by default was having UVs defined for just a subset of faces).

Fixed: The DOMRenderer was not using the correct members from the result of the projectScene() function, which ended up meaning that no DOM elements were being updated at all.

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

Is as it was before, but I implemented the event dispatching in a different way (checking the distance of the object position between frames). Also renamed the 'update' event to 'change'.

controls.addEventListener( 'change', render );

Right now only misc_camera_trackball.html uses this.

At least till we don't have this solved somehow better I think we should keep the old one. New one makes everything using it feeling broken, it's distracting.

Moved new event-driven `TrackballControls` into `TrackballControlsExperimental`. For the moment used just in "misc_camera_trackball.html" example.

Now we can do things like this:

controls = new THREE.TrackballControls( camera );
controls.addEventListener( 'update', render );

Sadly, some examples are slightly broken until we have better pipeline for assets load complete event dispatching.

Seems horse model was wrong, it had one extra frame at the end (almost identical to the first frame), which caused our animation playback code to be incorrect in order to accommodate for this.

Side-effect was that two frame animations were completely broken.

Bah.

(ERROR - variable instance_material is undeclared)

Adds a check for the instance when normals are provided as part of the vertices element in the collada file and supplies the normals from there (as per the collada spec). If normals still aren't supplied, this defaults to calculating the vertex normals via Geometry.computeVertexNormals().

Also updated build script to fill in missing dependency (ImageUtils => DataTexture).

Collada files normally name the materials, so this adds the name property to the material and puts that name value into it.

As per discussion in #1256

Also improved error reporting in JSONLoader (getting DEPRECATED errors for incorrect URLs was really confusing).