Move the Main instruction from register to virtual

also needs a branch in register.
This way the register level is self sufficient
(noticed while writing debugger)

lib/virtual/instruction.rb

@@ -26,3 +26,4 @@ require_relative "instructions/method_return"
 require_relative "instructions/new_frame"
 require_relative "instructions/new_message"
 require_relative "instructions/set"
+require_relative "instructions/virtual_main"

lib/virtual/instructions/virtual_main.rb

@@ -0,0 +1,19 @@
+module Virtual
+
+  # This starts the Virtual 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 VirtualMain < Instruction
+    include Positioned
+
+    def initialize method
+      @method = method
+    end
+    attr_reader :method
+    def word_length
+      4
+    end
+  end
+end

lib/virtual/machine.rb

@@ -124,7 +124,7 @@ module Virtual
       return if @booted
       boot_parfait!
       @init = Block.new("init",nil)
-      @init.add_code  Register::RegisterMain.new( self.space.get_init )
+      @init.add_code Virtual::VirtualMain.new( self.space.get_init )
       @booted = true
     end