lilyglyphsStyle.sty: Modify \emmentaler

I want that word to be highlighted only a few times.
But then in a more beautiful way.
lilyglyphs.sty: Adjust \lilyglyphs scaling

As this command is mainly intended for use in the lilyglyphs manual
it should be optimised for use with the text font of the manual
lilyglyphsStyle.sty: Move font selection to dedicated package

Remove dependency of lilyglyphsStyle.sty from our font selection.
The files generated by the Python scripts \use lilyglyphsStyle,
so they shouldn't use non-standard files/fonts because that would
raise errors on most users' computers.
Move glyphlist and lilyglyphs-logo dirs below documentation

in order to make the directory structure more organized
Add lilyglyphs_private structure

A structure to place additions without interfering
with the original package files.

TODO: For upload this directory has to be packed
into an archive file.
Manual: Revise QuickStart, Introduction and Installation
Manual: Review Usage Chapter
Manual: Reorder Chapters

Move Command Reference after Usage and before Internals.
Although the reference will grow longer and longer it seems like a good
idea to pull it more to the beginning of the manual.
For the average user it shouldn't be necessary to go through all the
internal stuff in order to reach the reference.
Manual: Review Reference of predefined commands
Manual: Review Writing predefined commands
Manual: Add Directory Structure
Manual: several small touches
Manual: Review Python Scripts Chapter
Manual: Add 'contributing'
Manual: Add license section
Merge branch Revision of Manual