Fix if statements hoisting, now that send is working

Same same, just have to remembe to actually execute the condition if it is a send
Having send a possible expression, removes one tmp variable and associated move, for a little extra work.
Next return and assign (rest)

lib/vool/variables.rb

@@ -28,8 +28,8 @@ module Vool
     def add_ivar( array )
       array << @name
     end
-    def to_s
-      "@#{name}"
+    def to_s(depth = 0)
+      at_depth(depth , "@#{name}")
     end
   end