fire: Unify command line and demo code

Change SPEED to FRAME_RATE.
text: Unify command line and demo code

Change SPEED to FRAME_RATE.
rainbow: Unify command line and demo code

Change SPEED to FRAME_RATE.
images: Unify command line and demo code

Change SPEED to FRAME_RATE.
Unify None checks
Change setup tab layout a bit
images: Show image load errors as message box
demo: Remove fixed window size
Unify keypress code
pong: Unify code between command line and demo