[I] Replace color picker library with app's own color picker

[therealbluepandabear]

Try to create app's own color picker to reduce dependencies on other libraries.

[Noitarud]

Do you think two palette adjustments on the drawing screen will work? One line for the palette hues (colours/white) and another line to select palette brightnesses (or instead of whitening or blackening select any off-white tone to mix* with the first).

The reason is if i want to add 24 hues with 4-8 brightnesses each, my palette will be rather long, but if i set it up with a hue interval and a brightness interval, the palette would be organised. Some may want the long palette if they have a small screen. Perhaps toggle between showing the hues at specific brightness level(s) and various brightnesses of specific hue(s, per line).

(* mixing type may need to be customised (kind of like how layers can be overlaid), if drawing a waterfall you may like to reduce by some fraction and add the second colour in the opposite fraction. Or if looking through glass you may need to only subtract the first's colours (unequal RGB) according to the second chosen.)