Don't try to flood the server with pipelined requests until we have an idea of its limits.
Don't try to flood the server with pipelined requests until we have an idea
of its limits.

* context.c
  (serf_connection_t): Add three fields to help us track how hard we're
  pounding the server.
  (write_to_connection): If we have a 'discovered' keepalive limit and we've
  hit the max already, hold off; count the number of requests we've sent and
  purposely send one more than the limit each time as a trial balloon.
  (read_from_connection): Update each time we get a completed response without
  getting a Conn: Close; if we go past our previous keepalive limit, then
  release the cap.
  (process_connection): Deal with HUP and ERR earlier for now.
  (link_requests): Move earlier in file.
  (serf_connection_reset): Clear out request count; insert held, but not
  delivered, requests *after* we've cancelled the previous requests - this
  preserves the ordering.

lazysoez/serf,wzugang/serf,Manouchehri/serf,sworda/serf,alex1818/serf,google-code-export/serf,pengdu/serf,stoneCC/serf,yesoce/serf,yesoce/serf,x-clone/serf,alex1818/serf,zhengcq315/serf,SirJson/serf,alex1818/serf,Manouchehri/serf,soufianeEL/serf,muthusuba/serf,zhupan/serf,SirJson/serf,pengdu/serf,Manouchehri/serf,blueszhangsh/serf,justinweb/serf,google-code-export/serf,stoneCC/serf,idomon/serf,soufianeEL/serf,yesoce/serf,muthusuba/serf,TommyU/serf,liuzongquan/serf,google-code-export/serf,idomon/serf,lazysoez/serf,Manouchehri/serf,krime/serf,muthusuba/serf,soufianeEL/serf,sworda/serf,sworda/serf,idomon/serf,liuzongquan/serf,wzugang/serf,zhupan/serf,lazysoez/serf,pengdu/serf,blueszhangsh/serf,KyleSanderson/serf,blueszhangsh/serf,blueszhangsh/serf,justinweb/serf,x-clone/serf,wzugang/serf,wzugang/serf,krime/serf,google-code-export/serf,krime/serf,x-clone/serf,sworda/serf,lazysoez/serf,soufianeEL/serf,krime/serf,TommyU/serf,SirJson/serf,x-clone/serf,muthusuba/serf,liuzongquan/serf,SirJson/serf,yesoce/serf,justinweb/serf,zhupan/serf,alex1818/serf,TommyU/serf,idomon/serf,KyleSanderson/serf,zhengcq315/serf,KyleSanderson/serf,liuzongquan/serf,TommyU/serf,stoneCC/serf,zhengcq315/serf,pengdu/serf,KyleSanderson/serf,zhengcq315/serf,stoneCC/serf,zhupan/serf,justinweb/serf