make block replace take array or single instruction

lib/register/call_implementation.rb

@@ -11,7 +11,7 @@ module Register
       block.codes.dup.each do |code|
         next unless code.is_a? Virtual::FunctionCall
         call = RegisterMachine.instance.call( code.method )
-        block.replace(code , [call] )
+        block.replace(code , call )
       end
     end
   end

lib/register/set_implementation.rb

@@ -10,7 +10,7 @@ module Register
           to = RegisterReference.new(:r0)
           tmp = RegisterReference.new(:r5)
           move = RegisterMachine.instance.ldr( to , tmp , code.to.index )
-          block.replace(code , [move] )
+          block.replace(code , move )
         else
           raise "Start coding #{code.inspect}"
         end