Add encoder control for setting color space

Add encoder control for setting color space

This commit adds encoder side control for vp9 to set color space info
in the output compressed bitstream.

It also amends the "vp9_encoder_params_get_to_decoder" test to verify
the correct color space information is passed from the encoder end to
decoder end.

Change-Id: Ibf5fba2edcb2a8dc37557f6fae5c7816efa52650