Update module_ex.rb code documentation and code style

Didn't look good on rubydoc.info: http://i.imgur.com/469N92P.png

lib/liquid/module_ex.rb

@@ -13,6 +13,7 @@
 #     def an_allowed_method
 #       'this comes from an allowed method'
 #     end
+#
 #     def unallowed_method
 #       'this will never be an output'
 #     end
@@ -26,7 +27,7 @@
 #       'and this from another allowed method'
 #     end
 #   end
-# end
+#
 #
 # usage:
 #   @something = SomeClass.new
@@ -41,16 +42,18 @@
 # association models.
 #
 class Module
-
   def liquid_methods(*allowed_methods)
     drop_class = eval "class #{self.to_s}::LiquidDropClass < Liquid::Drop; self; end"
+    
     define_method :to_liquid do
       drop_class.new(self)
     end
+    
     drop_class.class_eval do
       def initialize(object)
         @object = object
       end
+      
       allowed_methods.each do |sym|
         define_method sym do
           @object.send sym
@@ -58,5 +61,4 @@ class Module
       end
     end
   end
-
 end