Added call to _renderer.resetGLState() at the end of light loop in WebGLShadowMap.render(), updated WebGLRenderer.refreshUniformsShadow() to send inverse of point light position to shader. Fixes #7260.

Bug fix: Viewport not restored correctly when rendering point light shadows for scenes that contain multiple light types.

Fixed morphing, broken by #7236.

Includes more robust handling of custom materials (see #7153).

Updated cubeToUV() to a reduced-instruction version with minimal branching, and updated near plane values for shadow map cameras to be at least 1.

Point light shadow mapping now utilizes cube-to-2D projection, avoiding the need for a samplerCube in the shader.

Added checks for definition of POINT_LIGHT_SHADOWS in shaders for including point light shadow mapping code.

* Shorter (less typo-prone)
* More intuitive (also "aligns" with gl.POINTS)
* Makes a nice API (Mesh, Line, Points).