[Cin] Feedback on ColorSpace new plugin

[Andrea paz]

1- Thanks for the colorimetric data inside Resources/Info/Details. And
thanks for putting the choice of color space in Transcode. I find them
two convenient and important solutions. Later on I'll also ask to put
the Transfer Characteristic Function and the Color Matrix; for now I'm
afraid of making GG too angry. ;-)

2- Implementing DCI-P3 is not so important, you can always use
OpenDCP. Useless to waste time if not requested by several people.