progress: Track total times following redirects

Update the progress timers `t_nslookup`, `t_connect`, `t_appconnect`,
`t_pretransfer`, and `t_starttransfer` to track the total times for
these activities when a redirect is followed. Previously, only the times
for the most recent request would be tracked.

Related changes:

  - Rename `Curl_pgrsResetTimesSizes` to `Curl_pgrsResetTransferSizes`
    now that the function only resets transfer sizes and no longer
    modifies any of the progress timers.

  - Add a bool to the `Progress` struct that is used to prevent
    double-counting `t_starttransfer` times.

Added test case 1399.

Fixes #522 and Known Bug 1.8
Closes #1602
Reported-by: joshhe on github