visualizer actions

[pashute]

• [x] theme fg color selector (header + button)
• [x] theme bg selector (list + main)
• [x] header color selector
• [x] background image selector
• [x] background color selector (list + main)
• [ ] header logo selector (with stretch and tile)
• [ ] font family control dropdown
• [ ] selected simulator font and text features
• [ ] theme color chooser regions (currently 1 sample)

[pashute]

• [ ] fix theme color selector image-map bug https://github.com/clarketm/image-map