Multiple languages for SLAs and the SLA UI can be added via the CPack
variables CPACK_DMG_SLA_DIR and CPACK_DMG_SLA_LANGUAGES. For each
language defined in the languages variable, CPack will search for
<language>.menu.txt and <language>.license.txt in CPACK_DMG_SLA_DIR.
If the sla directory variable is not defined, the old behaviour using
CPACK_RESOURCE_FILE_LICENSE is retained.
Drop #end and #module. Convert #section to a subsection header.
Convert #variable to the cmake domain "variable" directive.
Convert #macro to the cmake domain "command" directive.
Perform minor formatting fixes in text near these changes.