bookmarklet.js support for danbooru2 + fixed most issues with other sites

Added support for Danbooru2. All the remaining sites should now work without issue (regardless if the file is flash, or a sample image).

Had to remove support for oreno.imouto (now known as yande.re) due to them forcing https, which means the bookmarklet.js file can't be loaded due insecure content.
Can't see any way to fix this without including the entire .js file inside the bookmarklet.

This should address issue #350.