Made it possible to do "upload resume" over HTTP

  if(!checkheaders(data, "Accept:"))

    http->p_accept = "Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg, */*\r\n";

  if((data->bits.http_post ||

      data->bits.http_formpost ||

      data->bits.http_put) &&

     data->resume_from) {

    /**********************************************************************

     * Resuming upload in HTTP means that we PUT or POST and that we have

     * got a resume_from value set. The resume value has already created

     * a Range: header that will be passed along. We need to "fast forward"

     * the file the given number of bytes and decrease the assume upload

     * file size before we continue this venture in the dark lands of HTTP.

     *********************************************************************/

    if(data->resume_from < 0 ) {

      /*

       * This is meant to get the size of the present remote-file by itself.

       * We don't support this now. Bail out!

       */

       data->resume_from = 0;

    }

    if(data->resume_from) {

      /* do we still game? */

      int passed=0;

      /* Now, let's read off the proper amount of bytes from the

         input. If we knew it was a proper file we could've just

         fseek()ed but we only have a stream here */

      do {

        int readthisamountnow = (data->resume_from - passed);

        int actuallyread;

        if(readthisamountnow > BUFSIZE)

          readthisamountnow = BUFSIZE;

        actuallyread =

          data->fread(data->buffer, 1, readthisamountnow, data->in);

        passed += actuallyread;

        if(actuallyread != readthisamountnow) {

          failf(data, "Could only read %d bytes from the input\n",

                passed);

          return CURLE_READ_ERROR;

        }

      } while(passed != data->resume_from); /* loop until done */

      /* now, decrease the size of the read */

      if(data->infilesize>0) {

        data->infilesize -= data->resume_from;

        if(data->infilesize <= 0) {

          failf(data, "File already completely uploaded\n");

          return CURLE_PARTIAL_FILE;

        }

      }

      /* we've passed, proceed as normal */

    }

  }

  do {

    send_buffer *req_buffer;

    struct curl_slist *headers=data->headers;