Merge pull request #148 from remcohaszing/gh-pages

Don't add empty string value to valueless attributes
Move js, css to assets. Create benchmarks folder.
Fix grunt
Disable clean-css' advanced optimizations by default. Closes #147
Escape closing script tag. Closes #142
Update uglify.js to v2.4.13.

The file is generated with `uglifyjs --self -o uglify.js`.
Update _config.yml.
Fix tests.
Partially revert "Fix tests."

This reverts commit ee3c275904ac45df859594bed3c72c88e4aeb1f8.

The Web tests will only fail due to uglify's mangling.
Add a CHANGELOG.md.

Fix #149.
Update time-grunt dependency.