V1.0.1

Fleshed out the app. The user flow is now:

• Launch the EXE
• Click 2 points to define a rectangle
  • or press a number 1-9 if you've already saved a region before 
  • or 0 to cycle through all saved regions
• The window defaults to inversion, and keeps focus. 
• Press c to toggle colour on/off, i to toggle inversion, and w to cycle through 4 white points levels. 
• You can also adjust size with usual window manipulation if you want to adjust it a bit
• Optionally, press Ctrl+1-9 while focused to save a screen region, including rect and colour effects.  
• Optionally, press Ctrl+Shift+P (this is a global shortcut) to pin the window. 
  • In this mode, it's transparent to all input events (except the global toggle Ctrl+Shift+P) and therefore no longer moveable. 
  • But you can now click 'through' the colour filter to your other apps.
  • Upon pinning, focus is restored to the app that had focus on startup.
• Most shortcuts (apart from region slots) are configurable in a text file that is created on first run.