Support other ways to add to library

[rozbb]

Currently you need to open RTMS in order to add an article to the library. It would be nice if there were a bookmarklet or share target that let you add it directly from the page. Push To Kindle is a good example of such a bookmarklet.

This has other benefits too. With a bookmarklet, you could possibly do text extraction client-side. This lets users with, e.g., Bloomberg accounts to add Bloomberg articles to their library without having to give RTMS their login.