warnings, one C99 thing and the bad pointer sent to the callback

CURLOPT_OPENSOCKETDATA to set a callback that allows an application to replace
the socket() call used by libcurl. It basically allows the app to change
address, protocol or whatever of the socket. (I also did some whitespace
indent/cleanups in lib/url.c which kind of hides some of these changes, sorry
for mixing those in.)

CURLE_PEER_FAILED_VERIFICATION (standard CURL_NO_OLDIES style), and made this
return code get used by the previous SSH MD5 fingerprint check in case it
fails.

CURLOPT_SSH_HOST_PUBLIC_KEY_MD5 and the curl tool --hostpubmd5. They both make
the SCP or SFTP connection verify the remote host's md5 checksum of the public
key before doing a connect, to reduce the risk of a man-in-the-middle attack.

function init_id_key() under low memory conditions.

Added test case 1008 to verify. Note that #47 is still there.

attempt to force smaller bits to get read by clients.

CURLOPT_POST301 written by Philip Langdale

it gets passed the initial value as an argument.

supported range.

in as argument!

target called 'filecheck' so that if you run 'make filecheck' in this directory
it'll check if the local files are also mentioned in the Makefile.am so that
they are properly included in release archives!

function do wrong on all input bytes that are >= 0x80 (decimal 128) due to a
signed / unsigned mistake in the code. I fixed it and added test case 543 to
verify.