Implement server-level application resolving about dominate HOT 2 CLOSED

'''
format of httpserver.sites:

[ SPECIFIER, HANDLER, ... ]
where SPECIFIER is one of:
  * a regular expression string - matches that hostname (or uri, in a sub-handler)
  * an HTTP error code          - matches that error code
  * HTTPError                   - matches all errors
  * None                        - matches None or the empty string
  * True                        - matches everything

If no specifiers match, an HTTPError(404) will be raised.
If multiple SPECIFIERs match, the last one will be used. If the last one raises a 404 error, then the second last one will be used, etc.
Note that if a leaf-node (final handler) raises a 404, that error will be handled normally and will not cause the resolver to keep looking

and HANDLER is one of:
  * [ SPECIFIER, HANDLER, ...]  - to do further processing
  * a function object           - will be called with f(*args) where args is a list of all regex matches that were encountered in the entire processing of this request. The function's return value will then be used as a new HANDLER
  * a handler object            - will be called with .handle(httpserver, request, response, *args) (or .handle_error(..) if this is an error match)
  * None                        - do nothing
  * an HTTPError instance       - this error will be raised

'''

# an example:
sites = [

  True, [ 
    # example.zkpq.ca didn't match, redirect the user to the right hostname
    '^/.*$', HTTPError(302, 'http://example.zkpq.ca')
  ]

  '^example.zkpq.ca$', [
    '^/(\w+)$',   lambda x:pyyscript        ('.', '%s.py' %x), # need lambda to add '.py'
    '^/src(.*)$', lambda x:syntaxfileserver ('../..',  x),    # serve the source dir with highlighting. don't need a lambda here, but it works
    '^/doc(.*)$', fileserver('../',    x),    # serve the documentation 

    HTTPError:    lambda :pyyscript('.', 'error.py'), # generic error
    404:          lambda :pyyscript('.', '404.py'),   # specific error
  ]

]

# TODO: make pyy_httpserver acctually implement this!