Add Greek and Cyrillic glyph aliases (issue 316800043 by address@hidden)

[lemzwerg]

LGTM.  Note, however, that the new versions of URW fonts are considered
problematic, since they differ too much from the original set of fonts
(especially metrics) – this is the very reason that currently TeXLive
doesn't use them.

https://www.preining.info/blog/2015/08/sins-of-the-past/

Admittedly, this problem doesn't directly affect lilypond, especially if
it delivers the fonts in a bundled form.

https://codereview.appspot.com/316800043/