Removed images from some boards.
Merge pull request #1224 from Wohlfe/v3

Removed images from some boards.
Polyfill canvas toBlob().
I couldn't find the exact cause, I suspect people are just adblocking random elements and expect not to break things.
$.xhr will now deal with `Last-Modified` and `If-Modified-Since` headers itself.
Merge branch 'v3' into watcher