Sync libfetch and fetch with FreeBSD.

Sync libfetch and fetch with FreeBSD.

* Plug a memory leak in libfetch.

* First try to change the entire directory path at once. If an error
  occurs, fall back to the default method of one CWD per directory
  element.

* fetch will now show the transfer speed while fetching (better progress
  output format).

* Numerous other fixes.