Pre-Release Tasks/Bugs

[fritzy]

• earth: replace deserts toggle with city lights toggle
• earth: hook up random parameters button
• earth: make random/regenerate more obvious
• earth: fix regenerate on load and rand parameters for web
• gas giant: add 3 gradient presets
• gas giant: add intensity slider
• sun: add color pickers
• sun: add intensity and speed sliders
• earth + gas giant: add speed and direction slider
• earth + gas giant: fix initial load draw of orbit gizmo
• keep all bodies loaded
• fix screenshot button
• fix initial parameter sliders
• clean up and document shaders
  • nebula
  • rocky
  • gas
  • sun
• clean up and document gdscript
  • toy
  • rocky
• write README
• write LICENSE
• replace images and previews on itch.io