Remove sample coverage to keep in sync with glTF 0.8
Update model tests for glTF 0.8 update
Merge remote-tracking branch 'origin/master' into gltf-8-tweaks
Start of WEBGL_debug_shaders
Report when link fails
Fix deleteProgram
Upgrade knockout to 3.2.0

https://github.com/knockout/knockout/releases/tag/v3.2.0
Update CHANGES.md
Upgrade to CodeMirror 4.6

Everything works, except for autocomplete.  More cleanup and testing needed.
Fix Sandcastle autocomplete and doc support

Also remove Cesium-hint.js as it's no longer needed.
Update CHANGES.md

Also remove uneeded CSS class.
Fix gutters.
Merge remote-tracking branch 'origin/master' into codemirror-4.6

Conflicts:
	CHANGES.md
Merge remote-tracking branch 'origin/master' into knockout-3.2.0

Conflicts:
	CHANGES.md
Update simple.czml

This gets rid of curved access lines and is also a much smaller file
due to recent toolchain upgrades.
Refactor shader source classes, in order to work around a Firefox bug.

The Firefox bug prevents shaders from compiling with the CORDIC algorithm, so we detect Firefox and fall back to the original algorithm.  Issue #2197.

The overall goal of the refactoring is to allow `#defines` to affect built-in functions, which was not possible before.  In order to do this, we need the `#defines` to appear at the top of the source, so I've merged the procedural shader generation previously done in `ShaderProgram` with the generation done in `createShaderSource`.

* `createShaderSource` (private) is removed and replaced by `ShaderSource`. `ShaderSource` now manages an array of `#defines`, concating source shaders, and automatically including built-in functions, keeping everything in the correct order.
* `ShaderCache` (and by extension `Context.createShaderProgram` and `Context.replaceShaderProgram`) now accept either `ShaderSource` objects, or a single string, for vertex and fragment shaders.
* `ShaderProgram` constructor (private) now takes an options object.  It also exposes the vertex and fragment shaders as `ShaderSource` objects instead of strings.  External code can still clone the `ShaderSources` and then screw around with the implementation to make new shaders procedurally, as `OIT` does.
sort requires
remove unused modules
fix typo
Further compress terrain normals before creating vertex buffer.