lilypond distance changes from 2.11.39 to 2.18.2

[Veronika Neumann]

Hi there,

some time ago I created a songbook with lilypond version 2.11.39. Now
I'm working with the current lilypond version (2.18.2). And I would like
to have the output pdf (via pdflatex) look the same as with the old
version. But it doesn't. Especially the vertical distances changed, e.g.
the space between chords and staff is smaller.

Which indent/margin/distance definitions changed from version 2.11.39 to
version 2.18.2? Where can I find them (which file(s))? How can I use the
"old" layout settings with the current lilypond version?

I also have some songs that are shorter than one line. With the old
version the staff was stretched to paper width, with the new version
it's not streched and takes up only the left half of the page.

How can I reverse this behavior?

Many thanks in advance!
Veronika