[metapost] mpman: title page

[Karl Berry]

    What do people think?

Personally I don't see a reason to use the logo font on the title page
or anywhere else in the reference manual.  Not that I have any great
objection to it, but since John always wrote it in roman, why change?
FWIW, I've switched to (almost) always using roman in TUGboat.

Best,
k

P.S. \logo was undefined in last night's run of mpman.tex.  Didn't check
if it's already been fixed, sorry ...