Fix http generated images path when using Compass sprites

Otherwise compass uses '/source/images' for the sprite image URL

config.rb

@@ -6,6 +6,7 @@
 # Publishing paths
 http_path = "/"
 http_images_path = "/images"
+http_generated_images_path = "/images"
 http_fonts_path = "/fonts"
 css_dir = "public/stylesheets"