Enabled Lisp extension files to be loaded from ATL source file. ...

Also added option to show license to interactive start menu, and
various small bug fixes/additions.

Added races and character classes, wrote safe-guard against circular imports.

Enabled recursive loading of ATL files, implemented option command behaviour. ...

The latter caused many headaches, and great joy in its completion :D

Integrated interpreter.lisp with atlantis.lisp, various bug fixes.