buildscripts/mutopia-index.py ; horn Konzert

[Graham Percival]

buildscripts/mutopia-index.py  generates
http://lilypond.org/doc/v2.6/examples.html

in the .py file, there's a comment:
        # FIXME: include warning if it uses \include
        # files.

I believe that the horn Konzert is the only file which
uses \includes.  Could we either drop it from the
examples page or actually generate a warning?

The warning could even be a simple hard-coded

if (file_name == 'mozart-hrn-3.ly')
  lst.write ('Please see foo/bar/baz/ for the other files')


Cheers,
- Graham