* scm/output-ps.scm (header): Papersize from paper.
* scripts/lilypond.py (global_latex_preamble): Oldish behaviour
for classic output.
* tex/lilyponddefs.tex (interscoreline): Oldish behaviour if
lilypondclassic is defined.
(lilypondstart): Oldish behaviour if lilypondclassic is defined.
* input/regression/between-systems.ly: Remove.
* python/lilylib.py (get_bbox): Fix regular expression
for bounding box.
* tex/lilyponddefs.tex (lilypondpagebreak): New overridable macro.