Add support for uint8_t and uint16_t bitsets. These pack very well in some structs. Support is required so the templates work as expected. Also packs the Shader map into 8 bits. This includes a workaround for an unusual warning generated by MSVC. Bug: angleproject:2462 Change-Id: I804d1b9370b3951343718385210dec7d37700d73 Reviewed-on: https://chromium-review.googlesource.com/1091135 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Frank Henigman <fjhenigman@chromium.org>