Calling super from AASM.included

Reason for this is rails gets uppity if you include AASM in a model, then subclass that model (STI.) You can end up with "can't dup NilClass" errors and it's all very confusing.

Calling super is considered playing nicely with other code anyway.

lib/aasm/aasm.rb

@@ -11,6 +11,7 @@ def self.included(base) #:nodoc:
     unless AASM::StateMachine[base]
       AASM::StateMachine[base] = AASM::StateMachine.new('')
     end
+   super
   end
 
   module ClassMethods