Implement support for "DaVinci Wide Gamut" colourspace.

[KelSolaar]

Via @jedypod.

References

r: 0.8000, 0.3130
g: 0.1682, 0.9877
b: 0.0790, -0.1155
w: 0.3127, 0.3290

[KelSolaar]

Seems like BMD made an error when implementing the colourspace in Resolve and their whitepaper described another set: https://documents.blackmagicdesign.com/InformationNotes/DaVinci_Resolve_17_Wide_Gamut_Intermediate.pdf?_v=1607414410000

      x      y
red   0.8000 0.3130
green 0.1618 0.9877
blue  0.0790 -0.1155
white 0.3127 0.3290

[KelSolaar]

Some more weirdness:

>>> colour.primaries_whitepoint(np.array([[0.70062239, 0.14877482, 0.10105872], [0.27411851, 0.87363190, -0.14775041], [-0.09896291, -0.13789533, 1.32591599]]))
(array([[ 0.8   ,  0.313 ],
       [ 0.1682,  0.9877],
       [ 0.079 , -0.1155]]), array([ 0.3127,  0.329 ]))

[KelSolaar]

From private conversations between BMD and @fredsavoir, the primaries as given in Resolve are correct. Closing this one!