Things to be implemented
------------------------

Vaguely prioritised list of things to be implemented at some point. Maybe
even before 1.1 is released.

* Check for updated pages & optionally download (If-Modified-Since)
* Stop using file existance as criteria for download; maintain a table
  of URLs already downloaded. Should be implemented at same time as
  If-Modified-Since, as both used together gives mirror updating. Also
  allows 'check for broken links but don't store downloaded files' option.
* Symlink redirecting pages?
* Download status display
* Keep-Alive connections
* Concurrent connections?
* Proxy servers