internal: Try handling URLs in a consistent way. * Now URLs passed to, and returned from, routes will always be absolute URLs, i.e. URLs including the site root. * Validate the site root at config loading time to make sure it starts and ends with a slash. * Get rid of unused stuff. * Add tests.

import os


def slashfix(path):
    if path is None:
        return None
    if isinstance(path, str):
        return path.replace('/', os.sep)
    fixed = []
    for p in path:
        fixed.append(p.replace('/', os.sep))
    return fixed