[Bf-committers] Color storage - color pickers

[Antony Riakiotakis]

There is something thing that looks error-prone with the current color
storage scheme: Any colors stored as PROP_GAMMA will be stored in the space
of the device the file was saved in. This will invalidate those if the file
is opened on a computer where the display device is different. Maybe all
color properties should be stored as linear (or reference space) instead?