routing: Simplify how routes are defined. * No more declaring the type of route parameters -- the sources and generators already know what type each parameter is supposed to be. * Same for variadic parameters -- we know already. * Update cache version to force a clear reload of the config. * Update tests. TODO: simplify code in the `Route` class to use source or generator transparently.

PRIORITY_FIRST = -1
PRIORITY_NORMAL = 0
PRIORITY_LAST = 1


class Formatter(object):
    FORMAT_NAMES = None
    OUTPUT_FORMAT = None

    def __init__(self):
        self.priority = PRIORITY_NORMAL
        self.enabled = True

    def initialize(self, app):
        self.app = app

    def render(self, format_name, txt):
        raise NotImplementedError()