HTTP server

for each *_perform(). It makes things a lot easier, as the first one that
detects the error get to write the final error reason...

even under normal unixes.

that is dead, because it can only find one entry anyway and if that is dead
there won't be any other entry that matches

information as well. Improves debug outputs etc.

rely on the new go-ahead-and-try mechanism that I just added to Transfer()

new logic can retry the same operation on a new connection!

- which now is made using a macro named FTPSENDF. I turned it all caps just
to make it more visible that it is in fact a macro.

accidentally did after the Curl_tvdiff() interface change

connection. The simple socket-check is not enough in these cases.