Update emmentaler fonts to 2.16.2
add emmentaler-brace otf font file

This font hasn't been used so far, but I want to have it in the repo,
just to be sure it is available if needed.
Rebuild image glyphs with 2.16.2
Update \version in generated .ly files to 2.16.2

They had originally been 2.17.4
(which was current when I created them first),
but I think they should always be 'latest stable'