Merge pull request KhronosGroup#2646 from johnstiles-google/parseconst

Fix mat4x2(scalar) constructor.

Merge pull request KhronosGroup#2624 from greg-lunarg/v011004000

Update CHANGES for 11.4.0

Merge pull request KhronosGroup#2620 from greg-lunarg/v011003000

Update CHANGES for 11.3.0

Merge pull request KhronosGroup#2543 from greg-lunarg/chg11.2.0

Update CHANGES.md to 11.2.0 to sync with current tagging.

Version 11.1.0

Version 11.0.0

Merge pull request KhronosGroup#2356 from greg-lunarg/kg112

Update spirv-tools known-good to most recent stable

Update README.md

stable release April 27, 2020

2nd candidate for this week's LunarG SDK build.