Make font controls easier to use

use radio buttons and a slider (range input)
instead of dropdowns, which require two clicks for every change
Fix initial font setup; tweak styling of controls
fix previous commit, adjust css

css adjustments:
- font-size is invalid within @font-face;
- harmonize vertical alignment of output element
  so it works the same way for both chrome and firefox
Merge pull request #57 from waldir/gh-pages

Make font controls easier to use (one-click)