fix the initial jump

lib/register/instructions/register_main.rb

@@ -1,14 +1,19 @@
 module Register
 
   # This starts the register machine machine at the given function.
-  
+
   # The implementation is most likely a jump/branch , but since we have the extra layer
   # we make good use of it, ie give things descriptive names (what they do, not how)
 
   class RegisterMain < Instruction
+    include Positioned
+
     def initialize method
       @method = method
     end
     attr_reader :method
+    def word_length
+      4
+    end
   end
-end
+end