Added better random in GeometryUtils. Added possibility of using custom depth material for shadow maps.

DataTexture can be used in the same places like image / video based Texture (WebGLRenderer-only).

To be used like this:

var width = 64, height = 64, bytes = 3;
var data = new Uint8Array( width * height * bytes );

// fill data array with values 0 .. 255

var texture = DataTexture( data, width, height, THREE.RGBFormat );
texture.needsUpdate = true;

For the moment only UNSIGNED_BYTE type is supported.

Added alphaTest parameter to base Material plus corresponding shader chunk in standard materials implementation.

This is for having on/off transparency without sorting using threshold value in alpha channel of diffuse texture.

By default it's switched off (alphaTest = 0).

AlphaTest is not yet handled in shadow maps. This would require passing of diffuse texture to depth material in shadow map render step (and more permutations of depth material).

This cut TextGeometry creation time almost by half.

Didn't help much, there is still a lot of garbage collection showing up in profiler (~18 %).

Also, real hotspot are loops in Shape.Utils.triangulateShape (with ~27% of total time spend on Vector2.equal). This maybe could be refactored with hashmaps.

- moved 3d-only text parameters from TextPath into TextGeometry
- added safeguard for bevelSize and bevelThickness not affecting shape size if bevel is disabled
- updated text examples as now TextGeometry is not anymore centered

Note: shadow maps as currently implemented are very fussy, they need tons of tweaking to look halfway decent. Also current implementation doesn't do proper depth normalization. For some reason this gives better results than the "right way".

Doesn't seem to produce visible difference.

Nine tap sampling, by default it's on, switch off with:

renderer.shadowMapSoft = false;