Logo, Splash Screen, "Reggie Next," Error Checking

This commit includes the new Reggie Next logo, made by Meorge.

It also includes a new splash screen based on the new logo, made by
Meorge and modified by me.

All instances of "Reggie!" have been replaced with "Reggie" or "Reggie
Next" - the exclamation point was getting too annoying.

The struct.error bug-checking code is better now. It's not intended to
fix the problem, but to print out a better error message that will help
me find the cause.