Simplify rule iteration

Avoid traversing rules twice, just check them all since single occurrences are
terminating.

Terminating is true as implied for .all? on empty sets.

Author: avit

lib/ice_cube/schedule.rb

@@ -384,7 +384,7 @@ def self.from_hash(original_hash, options = {})
     # Determine if the schedule will end
     # @return [Boolean] true if ending, false if repeating forever
     def terminating?
-      recurrence_rules.empty? || recurrence_rules.all?(&:terminating?)
+      @all_recurrence_rules.all?(&:terminating?)
     end
 
     def hash