Clean up whitespace
Refactor @font-face adding

1. Renamed styleString to the more descripting fontFaceRule.

2. Refactored injectCSS in jQuery instead of Plain Old JavaScript.

3. Adding only one <style> element, which may or may not improve
   performance (didn't profile yet).

4. Removed the 'rel' attribute from <style>, because it's not
   supposed to be needed.
Do things in batches

* Inject css for all fonts in one go
* Apply font-family to language tagged elements in one go per font family
Restore previous non-jQuery injectCSS and a bit of cleanup

Writing it in jQuery may be problematic and we aren't sure
that it's very helpful. Reverting until further investigation.
Merge pull request #23 from wikimedia/Nikerabbit-amire80-refactor-font-face

Nikerabbit amire80 refactor font face
Whitespace
Only append @font-face if it's not an empty string

Unbreaks the functionality broken in 11303b7, which caused
empty <style> elements.
Cleanup of comments and little code