Big question: whether to get rid of dummy socket on name resolve on Windows
outright (instead of the CURLMOPT_NODUMMY flag). On the one hand, the dummy
socket causes busy waits on some versions of Windows. On the other hand,
removing it will require code changes to curl windows clients - small
changes but code changes nonetheless.

Differences since last patch:
  * simpler timeout generation logic
  * More warnings about select() in the documentation
  * modified examples to handle maxfd==-1 on Windows

Other decisions:
  * won't use self-connect socketpair trick as some firewalls block it

-Costa