nacl: add supports_context_api implementation
nacl: add supports_context_api implementation

Currently only OpenGL ES 2.0 is supported.

v2: throw error only on erroneous input (Chad Versace)

Signed-off-by: Tapani Pälli <cdcb67a5e49297de94340ca09f25994bd5e7f762@intel.com>
Reviewed-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@intel.com>
Reviewed-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>

dcbaker/waffle,evelikov/waffle,chadversary/waffle,waffle-gl/waffle,waffle-gl/waffle,fjhenigman/waffle,chadversary/waffle,dcbaker/waffle,waffle-gl/waffle,fjhenigman/waffle,evelikov/waffle,fjhenigman/waffle,evelikov/waffle,dcbaker/waffle,waffle-gl/waffle,chadversary/waffle