Update index.html.

* add `meta charset`
* specify lang
* remove default type for css
* use https for the GitHub and Twitter links
Update uglify to v2.4.13.
README.md: add link to the website and JSHint.
master.css: Minor tweaks.

* make `textarea` resize only vertically
* be more explicit with `background`
* use the `font` shorthand when possible
Add missing semicolon.
Switch to the minified underscore build.
Fix a few variable redefinitions.
Slightly improve markup.
Ignore _site.
Rename uglify.js to uglify.min.js.
Minify JSHint with uglify.

This should be automated eventually.
Add _config.yml to ignore the unneeded files from the Jekyll build.
Enable strict mode.
Switch to `strong` instead of `b`.
Move comma first.

Makes it easier to maintain the list and spot missing commas.
Merge pull request #8 from XhmikosR/gh-pages

Minor tweaks