Reduce size of PDF files when inc. in *TeX docs

Reduce size of PDF files when inc. in *TeX docs

Issue 4251

This changes the way lilypond uses fonts to draw glyphs.

It avoids to used glyphshow for all emmentaler glyphs and
adds encoding vectors to the emmentaler fonts before they
are used. It also changes the ghostscript parameters used
to generate pdfs from postscript code.

These changes help to reduce pdf file sizes if you include
lilypond snippets in *TeX documents. The pdfs generated by
a patched lilypond and *tex themselves are _much_ bigger,
but if you run ghostscript and pdfsizeopt.py on those
files they implode.

Doc additions to the Usage Manual included:
Added a command line option
--bigpdf / -b, and documented that option in the german
and english versions of usage.pdf .

Internal hyperlinks are fully preserved with current
ghostscript git master.

External hyperlinks (GoToR) _to_ a file processed this
way are broken. Fixing this would require major changes
to ghostscript.

External hyperlinks _from_ a file processed this way to
other pdfs are preserved if the reader program isn't
broken (acroread is not broken in this respect, evince is).

For more details see Ghostscript bug #695747
<http://bugs.ghostscript.com/show_bug.cgi?id=695747#c22>