Hardware-less running!

Seems kind of counter-intuitive, but I wanted to make sure anybody could run this sketch, without having hardware hooked up.
Now, a camera is no longer required for the sketch to run. You do, however, still need at least one COM port. (I'll work that in soon.)

Changelog:
- Added functions to detect if camera isn't present, and compensates for this in the sketch, so it will run anyway.
- Added "Video Feed Unavailable" image when no cameras are detected.
- Arranged variables that are user-selectable towards the top.
- COM ports are now printed out in the console when the sketch fires up.
- COM port can now be selected by changing the ComSelection variable.
- Slight changes to camera display function to be able to run without a camera.