ListMenu Control Feature Parity with TornadoFx

[gtnarg]

Notes from the slack channel...

@gtnarg Two things. One is the themeProperty. It basically just adds/removes the theme string as a class on ListMenu. The other is a fix in ListItemSkin (called ListMenuItemSkin in TornadoFX) to support changes to the graphcisProperty:

@gtnarg I found another bug in the calculation of Side.BOTTOM. If you have configured graphicFixedSize, the y coords for the graphics is pushed down double of what it should have. (y += fixedSize - graphic.layoutBounds.height instead of y += (fixedSize - graphic.layoutBounds.height) / 2). (edited)

@gtnarg I found several issues with the ItemSkin's computePrefWidth and computePrefHeight. I think we didn't notice before because we didn't support icon only mode. I will commit soon. I'm also thinking about changing the colors of the default blue theme so that the selected item is lighter in color instead of darker. What do you think?

@gtnarg I also removed the default background insets and added a graphic class to the graphic node so it can be differentiated in css. I use that in the blue theme, will post a short video.

[edvin]

I'm working on supporting icon only mode better and it requires more changes, so we might just end up with copying the complete layout code from Kotlin to Java again. I will keep you posted.