texture generateMipmaps should check filter

Fix syntax error on older builds of IE11 #11440

Add uniform type for SAMPLER_EXTERNAL_OES uniform types

Optimize Ray.applyMatrix4 performance

ColladaLoader2: Added skinWeights and skinIndices

Fix some param check bug

Fix geometry.mergeMesh & merge check bug

Fix setViewport & setScissor pixelRatio bug

Update MeshStandardMaterial.html

Update Textures.html

Disambiguation re: https://github.com/mrdoob/three.js/issues/11367#issuecomment-306245201
Clearly describe the expected format of each type of cubemap image, and the resulting render.  The Cube*Mapping settings were detailed explicitly enough, but users coming from other contexts may know the other two by different names.  E.g. in the popular Unity and Unreal game engines, "spherical" reflection and HDRI maps implicitly mean lat-long.

Regarding https://github.com/mrdoob/three.js/issues/11452#issuecomment-306533171
Clarify requirements on the environment map for advanced use cases.

ColladaLoader2: Improve processing of visual scene

[glTF] Update all examples to glTF2.0