start writing parfait witout the module

Parfait classes must be unscoped. Now we start parsing Parfait, it must be without the module.
Luckily module_eval makes this a breeze.
Also remove string interpolation that is not yet processed

lib/parfait/factory.rb

@@ -1,4 +1,3 @@
-module Parfait
   # A factory has the one job of handing out new instances
   #
   # A factory is for a specific type (currently, may change by size at some point)
@@ -117,4 +116,3 @@ module Parfait
       obj
     end
   end
-end