- Use a simple regex to parse data uri instead of a hand-rolled parser, and
document what fields are considered mandatory.
- Use case-insensitive matching to find (fav)icons, instead of doing the same
query twice with different letter cases
- Add 'apple-touch-icon-precomposed.png' as a fallback favicon
- Reorder the queries to have i`con` first, since it seems to be the most
popular one. It used to be last, meaning that pages had to be parsed
completely 4 times, instead of one now.
- Minor factorisation in findIconURLsFromHTMLDocument
