Remove long-obsolete __length check
serializeMatcher, deserializeMatcher
Gestalt (de)serialization
Fix error in matcherEquals
More accurate canonicalization in erasePath
Better optionality-checking
GestaltLevel.pretty
Add missing case in matcherKeys
Fix error in serializeMatcher
Avoid accidental side cross-over in crossedGestaltLevelOp
Add Gestalt.metaLevelCount, .levelCount
use GestaltLevels.isEmpty instead of (accidental) inlining it
Actually shift levels for gestalt filtering
Avoid (accidental, erroneous) in-place modification of a GestaltLevel
Fix error in Gestalt.match
Distinguish input from output emptyLevels in mapLevels