for "module use", "module use --append", and "module unuse".
* Changed the global variable names (flags,current_module) to
(g_flags, g_current_module) to identify their ubiquity in the
module source.
fly, as it were. It's a powerful mechanism for dynamically changing
environment variables, aliases, X11 resources, etc.
It uses an embedded Tcl intrepretor, with a few extensions. Therefore,
it has a well defined language syntax.
Version 3.1 is GPL, and includes many improvements over the 3.0beta.
