Per working group conference call, added texImage3D back into WebGL
2.0 spec, and added non-normative text about preferring texStorage3D
and texStorage2D over texImage3D and texImage2D.
Remove extra commas from webgl-debug.js

This is done to improve compatibility with Closure compiler.
Make webgl-debug.js handle clear better

This change makes WebGLDebugUtils to be able to log clear calls better, by
separating the parameter into its bitwise-orred components if it is valid.
Unify indentation in webgl-debug.js

Change the tabs used for indentation to spaces and align indented blocks to two
spaces.
Merge pull request #754 from kenrussell/teximage3d

Per working group conference call, added texImage3D back into WebGL
Merge pull request #755 from Oletus/webgl-debug-improvement

WebGLDebugUtils improvement
Expression Lists in Declarator Initializers

Verifies expression lists in declarator initializers work correctly.

Shaders are of the form:
  precision mediump float;
  void main() {
      $(type) a, b;
      $(type) c = (b = $(initializer), a = b);
      gl_FragColor = $(asVec4);
  }

Test ensures c, b and a are initialized correctly.
Mixed array vs. non-array structs

Verifies that mixed (array vs. not array) struct declarators work correctly.

Shaders are of the form:
precision mediump float;
void main() {
    struct S {
        $(type) field;
    };
    S s1[2], s2;
    $(var).field = $(initializer);
    gl_FragColor = $(asVec4);
}

$(var) is replaced with s1[0], s1[1], and s2.
Don't require FS highp support in multiplication-assignment test
Merge pull request #758 from NVIDIA/conformance-highp-fix

Don't require FS highp support in multiplication-assignment test
Merge pull request #756 from RafaelCintron/expressionListInDeclaratorInitializer

Expression Lists in Declarator Initializers
Merge pull request #757 from RafaelCintron/structMixedArrayDeclarators

Mixed array vs. non-array structs
Add info log box to translate shader utility page
Merge pull request #759 from NVIDIA/translate-shader-info-log

Add info log box to translate shader utility page
Clean up and enhance scissor and viewport testing

Add one new test which ensures that initial scissor setting is correct and
that scissor does not change when canvas is resized.

Add black borders around canvases in scissor and viewport tests so that
debugging is easier.

Clean up unnecessary logging, typos, one unnecessarily included script.
Merge pull request #760 from Oletus/improve-scissor-tests

Clean up and enhance scissor and viewport testing
Add tests for passing simple ESSL3 shaders to WebGL 1

Currently, ANGLE-based browsers fail some of the tests, accepting
simple ESSL3 shaders in a WebGL 1 context.
Small fixes to the WebGL 1 ESSL3 shader test
Merge pull request #761 from NVIDIA/essl3-shader-bug-test

Add tests for passing simple ESSL3 shaders to WebGL 1
Add framebuffer texture attachment switching test