This commit adds two new devices, "M2SIO0" and "M2SIO1", to the AltairZ80
VM. These two independent devices emulate "raw" 88-2SIO ports that can
be used instead of the "SIO" device for attaching socket and serial
ports using TMXR.
These changes facilitate more robust parameter type checking and helps
to identify unexpected coding errors.
Most simulators can now also be compiled with a C++ compiler without
warnings.
Additionally, these changes have also been configured to facilitate easier
backporting of simulator and device simulation modules to run under the
simh v3.9+ SCP framework.
The first disk controller made by North Star was a single density
controller (MDSA). This was followed by the double density controller
(MDSAD) that is already supported in SIMH. This update adds support for
the single density controller as device MDSA. Since the controllers are
not software compatible, this update allows running of older software
designed for the MDSA controller.
