fix doc and add raw example

readme.textile

@@ -13,8 +13,14 @@ h2. Usage
 <pre>
 require 'asin'
 include ASIN
+# use the configure method to setup your api credentials
 configure :secret => 'your-secret', :key => 'your-key'
-item = lookup '1430218150
+# lookup an item with the amazon standard identification number (asin)
+item = lookup '1430218150'
+# have a look at the title of the item
 item.title
 => Learn Objective-C on the Mac (Learn Series)
+# access the internal data representation (Hashie::Mash)
+item.raw.ItemAttributes.ListPrice.FormattedPrice
+=> $39.99
 </pre>