xmp: Rename xmpPageRest to xmpPageTwo

I think 'rest' in the sense of 'remainder' is a 'false friend' for a German.
xmp: small doc retouches (Basic Usage)
.gitgnore: ignore minitoc help files
xmp: Move doc to documentation dir
Doc: Incl. xmp to main book

Include the musicexamples.sty documentation 
to the main openLilyLib.tex book
sample-tutorial: update syntax

change 'abstract' to 'authorAbstract'
xmp: start retouching doc (advanced use)
xmp: retouch doc (advanced usage)