Sebastien Willemijns reported bug #1603712

(http://curl.haxx.se/bug/view.cgi?id=1603712) which is about connections
getting cut off prematurely when --limit-rate is used. While I found no such
problems in my tests nor in my reading of the code, I found that the
--limit-rate code was severly flawed (since it was moved into the lib, since
7.15.5) when used with the easy interface and it didn't work as documented so
I reworked it somewhat and now it works for my tests.

RELEASE-NOTES

@@ -32,6 +32,7 @@ This release includes the following bugfixes:
  o curl_getdate() could be off one hour for TZ time zones with DST, on windows
  o CURLOPT_FORBID_REUSE works again
  o CURLOPT_MAXCONNECTS set to zero caused libcurl to SIGSEGV
+ o rate limiting works better
 
 Other curl-related news:
 
@@ -50,6 +51,6 @@ advice from friends like these:
  James Housley, Olaf Stueben, Yang Tse, Gisle Vanem, Bradford Bruce,
  Ciprian Badescu, Dmitriy Sergeyev, Nir Soffer, Venkat Akella, Toon Verwaest,
  Matt Witherspoon, Alexey Simak, Martin Skinner, Sh Diao, Jared Lundell,
- Stefan Krause
+ Stefan Krause, Sebastien Willemijns
 
         Thanks! (and sorry if I forgot to mention someone)