Import Minecraftia font for talk bubbles.
Simplify dir vars.
Import latest version of the intro text.
Change colors to green on black.

The blue background doesn't show well on the projector unless it's
weirdly bright for monitors.  Green-on-black should look decent on both
monitors and the projector.
Fixup Stroustroup-style function braces.
Add global config.
Allow starting scene to be set from command-line.