Some websites are using images of O(10kB) when not )O(100kB) for their
favicons. As miniflux only displays them with a 16x16 resolution, let's do our
best to resize them before storing them in the database. This should make
miniflux consume less bandwidth when serving pages, for the joy of mobile users
on a small data plan.
Of course, images that already are 16x16 aren't resized.
- 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
