move machine to module level

makes for shorter, more concise, access
also remove one more bug possibility
(reinitiation)

lib/virtual/passes/collector.rb

@@ -9,7 +9,7 @@ module Virtual
 
     def keep object
       return if object.nil?
-      return unless Machine.instance.add_object object
+      return unless Virtual.machine.add_object object
       #puts "adding #{object.class}"
       unless object.has_layout?
         object.init_layout

lib/virtual/passes/enter_implementation.rb

@@ -13,5 +13,5 @@ module Virtual
       end
     end
   end
-  Virtual::Machine.instance.add_pass "Virtual::EnterImplementation"
+  Virtual.machine.add_pass "Virtual::EnterImplementation"
 end

lib/virtual/passes/frame_implementation.rb

@@ -48,5 +48,5 @@ module Virtual
       end
     end
   end
-  Virtual::Machine.instance.add_pass "Virtual::FrameImplementation"
+  Virtual.machine.add_pass "Virtual::FrameImplementation"
 end

lib/virtual/passes/get_implementation.rb

@@ -13,5 +13,5 @@ module Virtual
       end
     end
   end
-  Virtual::Machine.instance.add_pass "Virtual::GetImplementation"
+  Virtual.machine.add_pass "Virtual::GetImplementation"
 end

lib/virtual/passes/send_implementation.rb

@@ -30,7 +30,7 @@ module Virtual
           else
             # note: this is the current view: call internal send, even the method name says else
             # but send is "special" and accesses the internal method name and resolves.
-            kernel = Virtual::Machine.instance.space.get_class_by_name("Kernel")
+            kernel = Virtual.machine.space.get_class_by_name("Kernel")
             method = kernel.get_instance_method(:__send)
             new_codes << MethodCall.new( method )
             raise "unimplemented: \n#{code}"