[metapost] New MPlib beta

[Taco Hoekwater]

Dan&Jan Luecking wrote:
> 
> Thus:
> use progname,
> but %&MEM line overrides  that
> and -mem=MEMNAME or &MEMNAME on command line overrides that.

Thanks, I'll try to emulate this in the next beta.

> I do, however, remember the days when plain was the default
> for tex and metafont. In emTeX, this persisted through the
> late 90s, even in metapost. I don't know if that was ever
> the case in web2c.

That's what I recall as well. It's what happens if the
Pascal web change file does not do anything special.

Best wishes,
Taco