Renamed 400_handler, and added some additional handlers inside it.
Massive reworking of the static file serving. Now, static files are served using a custom handler, as part of the url router. `ecstatic` is no longer being used, and the static module has been removed entirely. These changes have removed a large amount of code, and made static file serving more flexible. Also included are some Readme fixes, some 50x handler fixes, and some other required bits. This fixes #4.