41CL use of EXCFG, RCLCFG and STOCFG

[Monte Dalrymple]

There are actually 26 configuration LABELS available. The last character can be
any of A-Z. It is possible for multiple configuration labels to point at the same
configuration NUMBER; it's just a label for convenience so you don't have to
remember which is which once they are all set up.

The RAM version of the IMDB is only for editing; the PLUG functions always use
the version in Flash.