Possible improvements people could work on:

- [USAGE] rethink intern/extern stuff. Especially when specifying
  --extern one should not have to also specify --intern suddenly.

- [BUGFIX] when an URL is found in the cache and it has a broken anchor,
  the broken anchor name is not displayed as a warning

- [BUGFIX] Displaying redirection info and warning from the cache
  is not correct when the URL is not a redirected URL.
  Example: URL http://a redirects to http://b. Both http://a and http://b
  are now cached. Then a check of http://b will display a (cached)
  redirection warning.
  Possible solutions:
    * do not cache aliases
    * generate separate urldata instances for aliases with the proper
      warnings (one still has to define what "proper" means here).

- [USAGE] make a nice GUI for linkchecker

- [FEATURE] warn if overall size of page (including images/flash/etc.) is
  too big. Right now, the page size is only html content.

- [FEATURE] Option to save downloaded pages. This could also be used to
  build an internal cache, however there are already a plethora of
  caching proxies we could use for that.