... to make all libcurl internals able to use the same data types for
the struct members. The timeval struct differs subtly on several
platforms so it makes it cumbersome to use everywhere.
Ref: #1652Closes#1693
Prevent `Curl_pgrsTime` from modifying `t_starttransfer` when invoked
with `TIMER_STARTTRANSFER` more than once during a single request.
When a redirect occurs, this is considered a new request and
`t_starttransfer` can be updated to reflect the `t_starttransfer` time
of the redirect request.
Closes#1616
Bug: https://github.com/curl/curl/pull/1602#issuecomment-310267370
