added github corner, docs, code highlight, changed articles

README.md

_config.yml

_includes/github-ribbon.html

_includes/head.html

_layouts/default.html

_layouts/page.html

_posts/2013-12-23-helloworld.md

_posts/2014-01-15-xml.md

_sass/_highlight.scss

_sass/_styles.scss

css/main.scss

docs.md

images/dark.png

images/markdown.png

images/standard.png

index.html