Provide way to automatically displace fullpage examples on odd/even pages

[uliska]

So far we only include complete pdf pages, and the author has to provide suitably laid out scores.

However it should be possible to provide a onesided score that is then offset accordingly (the creation of such a score should be simplified by the LilyPond configuration files)

We'd have to determine odd/even status within \includepdf's pagecommand.
I have asked here how to determine the actual margins of our document: http://tex.stackexchange.com/questions/101829/how-can-i-determine-the-actual-inner-and-outer-margins

The actual margins of the included score have to be set and cannot be determined automatically.
I suggest: If no manual settings are given the score is included literally. If page margins of the score are supplied inthe LaTeX document the offset calculations take place.

To be thought about: What about the textheight of text and score? Do we have to do anything about that? Or is that plainly in the author's responsibility?
And should be support scaling the score to the text width/height?