Contains definitions of GLES1-specific states such as material /
lighting.

Tweaked the Color class for easier copying to uniforms / reading as a
float array.

This CL also adds the GLES1-specific state in GLES1State, which is then
part of the State class and is initialized to the spec's values if the
context major version is ES 1.

+ Some clang-format

BUG=angleproject:2306

Change-Id: I7fc3bd9a22ebf0ffcd98d931d0176f21e17b1c5c
Reviewed-on: https://chromium-review.googlesource.com/936424
Commit-Queue: Lingfeng Yang <lfy@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>