* scm/lily.scm (define-scheme-options): add clip-systems option.

* scm/lily.scm (define-scheme-options): add clip-systems option.

* scm/framework-ps.scm (dump-stencil-as-EPS-with-bbox): new
function
(dump-stencil-as-EPS): move bbox calculation from previous
dump-stencil-as-EPS
(output-framework): use -dclip-systems

* scm/lily-library.scm (filtered-map): new function

* scm/framework-ps.scm (clip-system-EPS): new function.
(clip-system-EPSes): new function.

* lily/paper-column.cc: add rhythmic-location to interface

* scm/define-grob-properties.scm (all-user-grob-properties): add
rhythmic-location property.

* scm/clip-region.scm: new file: rhythmic-location data type and
system-clipped-x-extent function.

* ly/init.ly: use (scm clip-region)

* lily/paper-column-engraver.cc (stop_translation_timestep): set
rhythmic-location for paper column grobs.

* lily/grob-scheme.cc (LY_DEFINE): minor cleanup