Allow Uint16Arrays uploads for texture_half_float
Specify reading from missing attachments

readPixels/copyTexImage2D/copyTexSubImage2D should generate INVALID_OP when reading from a missing attachment.
Changed oes-texture-float-and-half-float-linear tests to allow failure during glGenerateMipmap. This addresses https://github.com/KhronosGroup/WebGL/issues/408 .
Verify if component values are set correct

GLSL constructors : Added code to verify if component values are set
correct by constructor expression.
restoreContext() should INVALID_OP without loseContext()
Add a few more cases for testing struct scope.

Also, move the test from bugs/nested-structs-with-same-name.html
to misc/shader-struct-scope.html.
Merge pull request #551 from jdashg/spec-context-lost-ext

restoreContext() should INVALID_OP without loseContext()
Adjust 00_test_list.txt files.
Merge pull request #552 from zhenyao/scope

Add a few more cases for testing struct scope.
Added test for a shader compiler error when using ANGLE's D3D11 backend
Moved test to glsl/bugs, fixed some minor typos in the test
Merge pull request #554 from toji/d3d11-error

Added test for a shader compiler error when using ANGLE's D3D11 backend
Add test for polygon offset.
Merge pull request #553 from c0d1f1ed/master

Add test for polygon offset.
Removed unnecessary function and enums from EXT_blend_minmax extension spec
Typo. ext -> gl
Merge pull request #555 from toji/ext_blend_minmax_fix

Removed unnecessary function and enums from EXT_blend_minmax spec
moved EXT_sRGB from draft to community approved
moved EXT_frag_depth to community approved
Add coverage of uniform structures with non-vec4 elements.

Triggers a uniform packing bug in ANGLE's D3D11 backend.