struct: Add README-branching

Add a document to describe the desired branching work-flow - after the initial mess has been cleaned up the brute-force way.

This commit also serves for establishing the 'master' branch as separate from 'develop'.
Create README.md
Remove musicexamples directory

musicexamples is now in its own repository.
In fact it is the original one from before importing it into oll
Remove lilyglyphs folder

lilyglyphs now is in its own repository again.
In fact that repository is the original one from before importing it to oll