Change Mom to SlotMachine

rather large commit, but essentially a simple rename
Rationale in docs and blogs

lib/vool/macro_expression.rb

@@ -6,16 +6,16 @@ module Vool
       super(name , SelfExpression.new , arguments)
     end
 
-    def to_mom(compiler)
+    def to_slot(compiler)
       parts = name.to_s.split("_")
-      class_name = "Mom::#{parts.collect{|s| s.capitalize}.join}"
+      class_name = "SlotMachine::#{parts.collect{|s| s.capitalize}.join}"
       eval(class_name).new( self , *arguments)
     end
 
     # When used as right hand side, this tells what data to move to get the result into
     # a varaible. It is (off course) the return value of the message
-    def to_slot(_)
-      Mom::SlotDefinition.new(:message ,[ :return_value])
+    def to_slot_definition(_)
+      SlotMachine::SlotDefinition.new(:message ,[ :return_value])
     end
 
     def to_s(depth = 0)