Nice 404 Page not found page

So, this is my approach to the 404 "problem".

What I've done is basically define the `get` method in the BaseHandler and raise an `HTTPError` there. Then, add the `BasicHandler` as default handler for all unmapped request. Whenever a request is defined in another handler, the get method will be overwritten and then no HTTPError will arise. That's the nicer way I found for doing this... but this is also a "help wanted" pull request, in case you know something better :-)

![screen shot 2014-11-06 at 16 13 40](https://cloud.githubusercontent.com/assets/1574147/4938006/7b8d5862-65c8-11e4-87a7-6762b33f1dfa.png)

P.S: Also added the `RapidHighOutput` mode to the Q30 page..