Many improvements in router, renderer, page type. Temporary removed WSGI handler, because it should be within wetchy.py. Database added to pages as
self.database, passed parameters as self.PARAMS. Also added error handler (crappy one, but works), that will be rewrited soon.

Router receive ability to determine where to find files to serve in DEBUG mode. It will be site's public dir or, if not found, wetchy public dir. But if
Wetchy falls to emergency mode (any error) - this directory will be forced to Wetchy's public.