Surge++ Modulator Button Parameterization, Hover and so on.

[baconpaul]

Similarly to #1360 the modulation buttons (where you select LFO and stuff) have hard coded colors and those colors aren’t part of the type we use in the XML.

It’s basically the same fix as #1360 just with more colors (a background, an unselected and selected color, and a modulated unselected and selected color; and a blink color).

Also while fixing it, we should add a hover color gesture to the buttons like the glyph has.

[baconpaul]

Re-tooling the S++ plan so closing these issues.