* clear coat implementation.

* add physical variations to examples.

* add example file for physical materials

* adjust clearcoat range to 0-1 as original.

* switch example color to gray from yellow.

See https://css-tricks.com/snippets/javascript/javascript-keycodes/ for key codes.

* Fixed for non-HTML documents

* Replaced Image constructor with createElementNS

* Merging WebGLTextures.js

This didn't commit for some reason

* Fix Skeleton.pose() bug

* Clean up THREE.Skeleton

* add auto-builder.

* do an initial build when watching.

* add include directory in build-watch.

* incorporate zz85's suggestions.

* Water grid simulation w/ ShaderMaterial cloned from MeshPhongMaterial

* Water shader works with texture heightmap

* Added GPUComputationRenderer, I'm about to test it

* GPUComputationRenderer works with water simulation

* Interaction with mouse

* Added water viscosity, simple geometry for mouse picking

* Put pass thru shaders in GPUComputationRenderer. Some minor refactoring.

* Code revisison, added comments and explanations. Inverted mouse Y coord.

* Added GUI controls for some water parameters.

* Commencing conversion of birds gpu demo to GPUComputationRenderer

* Converted gpu birds demo to GPUComputationRenderer and fixed bugs in it.

* Solved mouse bug.

* Optimized smoothWater(), renamed some GPUComputationRenderer methods.

* Substituted old bird gpu implementation. Preparing for new demo.

* Removing old SimulationRenderer

* GPU protoplanets demo started. Minor tweaks in the other demos

* Starting to implement the particle demo

* $th component of texture now is usable. It was the GPUComputationRenderer
pass-through fragment shader.
Next thing to do is use a texture that contains (vx, vy, vz, mass).

* Particles already move. Next is gravity interaction.

* Gravity interaction done. Next is particle collision and aggregation.

* Particle collision works

* Added gui

* Some minor adjustments

* Added the two new demos to the list of examples

In the actions array of the Path, the last elements of the args array
need to be the x and y of the last point of the segment added to the
path.
Not the case with splineThru => cause an exception if you add an other
segment after the pline (without a moveTo).
Used the same trick as absellipse does.

the updateArcLengths in CurvePath must clear the local cache,
cacheLengths