Update Notes: v1.4.0

Update notes v1.3.2 → v1.4.0:

Enhanced modules, improved usability, fixed some bugs.

• Added an `Invoke` module for HTML
  
• Added a callback mechanism from JavaScript to Lua for HTML
  
• Added menu items to toggle transparent background and grids
  
• Improved continuous input of newline with indent for the code editor
  
• Improved debug behaviour if the debug panel is hidden
  
• Fixed a glitch after painting on a paletted image