Update modernizr.js to v2.7.1.
_includes/sidebar.html: fix indentation.
_includes/header.html: include the page class in body only if it exists.
Merge pull request #140 from XhmikosR/modernizr

Update modernizr.js to v2.7.1.
Merge pull request #141 from XhmikosR/includes

Includes
No License description missing that to complete sentence
Merge pull request #144 from randomecho/nolicence-description-typo

No License description missing a to to complete sentence
Clean up .gitignore and .gitattributes.
Ignore more files in _config.yml.