Make 'make install' ignore the new 'fuzzterm' binary.

Make 'make install' ignore the new 'fuzzterm' binary.

It's for regression testing and fuzzing, so there's no use for it if
you're not a developer working on the source.

Leaving it out of the 'make install' target in Makefile.gtk is no
trouble because that's already handled manually in Recipe by inserting
a giant hairy Makefile fragment to do the installation. But
Makefile.am was just setting bin_PROGRAMS to the full set of binaries
built, so for that one, I had to invent a new Recipe program category
[UT] which moves a particular binary into noinst_PROGRAMS.

While I was at it, I've retired the [M] program category, which has
been lying around unused since Ben's old Mac OS pre-X port.