Allow empty slot in parsers
Correct comparator make routine for editor context;

Fix logic of parent key in archetype catalogue;
Move definition of archetype catalogue path separator char to ARCH_CAT_ITEM;
More CDISC icons
Correct various editor related logic
Remove unneeded (and undocumented) slot-related error code.
Only remove occurrences, existence and cardinality from ADL 1.4 archetypes.