add integer to parfait

lib/parfait/integer.rb

@@ -0,0 +1,12 @@
+
+# Integer class for representing mathods on Integers
+# Integers are Values (not Objects), 
+# - they have fixed value
+# - they are immutable
+# you can *not* assign instance variables or methods
+
+# TODO how this idea works with Numeric ?
+
+class Integer < Value
+
+end