starting to clear up slots

mostly docs

lib/virtual/slots/frame_slot.rb

@@ -0,0 +1,12 @@
+module Virtual
+
+  # Slots in the Frame a re represented by instances of FrameSlot
+
+  # Slots in the Frame are local or temporary varialbes in a message
+  class FrameSlot < Slot
+    def initialize index , type = Unknown, value = nil
+      super
+    end
+  end
+
+end