error page, slight tweaks to sitemap generator

404/css/ie7.css

404/css/main.css

404/images/404.png

404/images/bubble.png

404/images/cat.png

404/images/cookie.png

404/images/dog1.png

404/images/planet.png

404/images/sky-background.png

404/images/sky-shine.jpg

404/index.md

_config.yml

_data/dogtalk.yml

_includes/dog.html

_layouts/error.html

_plugins/sitemap_generator.rb

_strings_en.yml