Kjetil Jacobsen reported an open file leak in file:// transfers of empty
files.

Andres Garcia pointed out that we searched for a slash badly since it is
converted and thus we must search for backslash on windows

fix warning

Replaced all uses of sprintf() with the safer snprintf(). It is just a
precaution to prevent mistakes to lead to buffer overflows.

The read callback can now return CURL_READFUNC_ABORT to stop a transfer.

Steven Bazyl and Seshubabu Pasam pointed out a bug on win32 when freeing the
path after a transfer.

initial support for "uploading" to file:// URLs

better bailing out in case of no memory

curl_global_init_mem() allows the memory functions to be replaced.
memory.h is included everywhere for this.

added comments

New authentication code added, particularly noticable when doing POST or PUT
with Digest or NTLM. libcurl will now use HEAD to negotiate the authentication
and when done perform the requested

New authentication code added, particularly noticable when doing POST or PUT
with Digest or NTLM. libcurl will now use HEAD to negotiate the authentication
and when done perform the requested POST.

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Use more curl_off_t variables when doing the progress meter calculations and
argument passing and try to convert to double only when providing data to the
external world.

another include to prevent warnings

more fixing to make the progress/getinfo stuff to work properly when doing
file: transfers too

include the proper header file too

fix progress data to be updated properly for file: transfers, as reported
by Jesse Noller

rename struct FILE to FILEPROTO, to prevent it from causing trouble with
the plain old FILE typedef.

Yet another curl_off_t printf format attempt, we now exclude the %-letter from
FORMAT_OFF_T to allow additional options to get specified, like with '"%5"
FORMAT_OFF_T'.

use FORMAT_OFF_T instead of CURL_FORMAT_OFF_T to reduce the complexity of
having to redef that name

Use CURL_FORMAT_OFF_T for printf()inf curl_off_t variables.

the now and start variables were never really used

I made the same fix here, that Tor already did in the ftp.c code. To make
sure this doesn't get weird on 64bit archs.

Dan Fandrich's cleanup patch to make pedantic compiler options cause less
warnings. Minor edits by me.

attempt to fix 64bit seeking for Windows, does it work?

use curl_off_t instead of off_t!