Fix implementation.
Merge master.
Modified accordion split sections for better html conformance.

The previous implementation allowed for accordions to be interrupted by
other elements like block grids.  Now the accordions do not contain a
block grid.  The separate accordion sections can be named and don't have
to be contained within the same dl.
Don't consider unnamed accordion attributes as a group.
Fix multi-expand as per PR #4941
Merge branch 'accordion-split-sections' of github.com:tejohnso/foundation into tejohnso-accordion-split-sections