#279 Numeric color picking

[William Kendrick]

Artists used to using more "professional" art software, web developers, etc., are used to representing colors using hexadecimal values (e.g., #000000 black, #FF0000 pure red, #888888 medium grey, etc.).

Some people may consider the values in decimal (e.g., 0-255 vs. #00 to #FF for each channel). Others may think in terms of percentage (0% to 100%).

Offering a way to see, and also edit (to select a new color) these values could be beneficial. This should probably be a feature that we hide when running in novice (and perhaps even beginner) --complexity levels.