This as convention helps spot leaking variables and makes it
easier to document variables for reader

It is intended, documented and assumed in later code that any test must
contain this executable.

Make it

 *  more flexible,
 *  more readable,
 *  faster,
 *  take care of manpages (not fully done yet),
 *  take care of dist list,
 *  little bit more polished in various other things.

A more conventional hierarchy

This new hierarchy makes it easier to work simultaneously on data and
the script, simplifies deployment to tempdir and makes the launching
script naming consistent with simple.sh.

"doc" (not manpages) is built and installed with others.

Otherwise tests with --prefix break since they operate from independent
folder.

This should be consistent with `ffoom` and `ffdoc`

 *  Instead of cp, use *install*.
 *  Store paths in paths.ini.
 *  Allow arbitrary number of path groups (bin, man, share, libexec...).

I have no idea what I was thinking when I added the pipe there...