Redesigned vector tool fill/stroke selection in relation to the working colors and selected layers

[Keavon]

[0HyperCube]

We should probably consider the fact that the default white fill has caused confusion among users such as myself and in #2403.

[Keavon]

Indeed, I'll be sure to include that aspect in the design, thanks for pointing that out again. It's been a choice that's gently nagged at me over time for being imperfect. The redesigned system should considerably improve the current conceptual model.