Bring over changes from the bitcointip userscript.

The userscript and the RES module have drifted apart over the last few months. I [merged the module changes](https://github.com/skeeto/bitcointip-user-js/commit/2cf1d370b384b9176fd5610beeee3bd74bd3ecf5) into the userscript, tested them, and then dropped it back in here.

This adds support for /u/bitcointip tipping syntax, disabled the subreddit indicator icon by default (since they're all enabled by the new syntax), and slightly tighter matching when choosing to show tip status icons.