User selectable block icon on toolbar for PB

The programmable block offers great "backend" functionality but poor interaction with the toolbar GUI. Putting a "run programmable block" command onto the toolbar provides no feedback to the user when subsequently viewing the toolbar as to what is being executed.

The build info mod at least adds the programmable block argument value to a separate toolbar-info GUI element, however the icon is always the icon for the programmable block iteslf.

I have a suggestion: When a player puts a programmable block execution onto their toolbar, allow the selection of any block icon to use as the icon for that toolbar slot. That could provide a lot of information at a glance.

Examples of situations where this would provide much more quality of life in the UI experience are basically limitless, but here are some:

• My PB takes an argument indicating an exact thrust override value to use for some subset of thrusters. I choose a thruster icon when adding the PB to my toolbar.
• My PB executes a program that keeps my ship level with the ground. I choose a gyro icon when adding the PB to my toolbar
• My PB executes a program that rids my ship of unwanted cargo. I choose an ejector icon when adding the PB to my toolbar
• ... and so on and so forth