Use a CSS sprite for the license images.

-3 HTTP requests.
Correct mistakes/omissions in the README.

The README says the license files are Markdown but they are not.
The text of the license should be wrapped to a 78 character width.
README.md: Break long lines.
README.md: no need to make the localhost a clickable link.
Merge pull request #159 from XhmikosR/license-sprite

Use a CSS sprite for the license images.
Merge pull request #160 from XhmikosR/readme

Readme
Specify box sizing.
Update application.css.

* clean up unused class and inherited properties
* move `.button` along with the rest of the selectors from that page
* remove `-moz-inline-stack` which was needed for old FF
Use qTip from the first mirror instead of the cloudflare distribution.
Work around issues with old IE.
Remove selectivizr-min.js.

It's not needed anymore as things work pretty good with old browsers.
Merge pull request #161 from XhmikosR/css

patch-2
application.css: Minor cleanup.

Move the common `color` property along with the other common properties and remove inherited properties.
Merge pull request #162 from XhmikosR/css-cleanup

application.css: Minor cleanup.
remove sub-licensability as a concept for public domain licenses/waivers
Merge pull request #163 from konklone/remove_sublicenses_for_pd

Remove sub-licensability public domain licenses/waivers
attempt to sort licenses in list
upgrade gems
Don't ignore all '#' URLs when running HTML::Proofer

Explicitly ignore the clipboard button from proofing, which was why the
:href_ignore was there in the first place.  Per
https://github.com/github/choosealicense.com/pull/104/files#r7311111.
Merge pull request #164 from github/sort-licenses

Attempt to sort licenses in list