Force WebGL2.
Add some WebGL2 fnuctions.
Add headers for OpenGL 4.2+.
Address review comments.
Merge branch 'incoming' into force-webgl2
Add GLES3 headers.
update news
zlib: Fix compilation warning in example.c
test_zlib works on Node, so re-enable it.
Merge pull request #2885 from dvander/glTexStorage2D

Add some GLES3 functions for WebGL2.
Correct opaqueFrontBuffer to work correct with 8bpp surface
Merge pull request #2890 from caiiiycuk/opaqueFrontBuffer

Fix copyIndexedColorData to work correct with opaqueFrontBuffer flag
use ArrayBuffer.transfer if present, and log out memory growth times
optimize copyIndexedColorData by storing colors in 32-bit chunks; #2890
Merge pull request #2888 from waywardmonkeys/zlib_tests

Zlib tests
minor cleanups in minifyLocals
misc site updates
do not warn on run deps existing when no asserts
Merge branch 'incoming' into force-webgl2