adds marker option to KeyValuePattern
removes unused regex from KeyValuePattern
adds return mark to kv pattern in recursive tree traversal
refactors termination of tree traversal
optimizes marked query for returning w/ earliest match
simplifies handling of termination & marked nodes in RecursiveTreeWalker
fixes marked node traversal for multiple marks
version bump
adds Query validation tests for queries with marked kv patterns
fixes traversal state for marked queries
adds marker setter to KeyValuePattern