1) Switched from using the registry to using a C++ map. This provides
an easy way to add...
2) A help command. With no arguments, this command prints a table of
commands. With arguments it prints a synopsis of the specified
command(s).
3) ioccrf() is now thread-safe with plans to add multiple remote
access via telnet. The value pointers have been removed from the
argument structures and a pointer to an array of argument unions is
passed to the registered callback routines.
4) All command/argument configuration structures are now const.
