CURLOPT_POSTREDIR.3: Added availability for CURL_REDIR_POST_303
CURLOPT_COOKIELIST: Added "RELOAD" command
test506: Fixed a couple of memory leaks in test
file: reject paths using embedded %00

Mostly because we use C strings and they end at a binary zero so we know
we can't open a file name using an embedded binary zero.

Reported-by: research@g0blin.co.uk
RELEASE-NOTES: synced with 53cbea22310f15
smtp: Fixed intermittent "SSL3_WRITE_PENDING: bad write retry" error

This patch fixes the "SSL3_WRITE_PENDING: bad write retry" error that
sometimes occurs when sending an email over SMTPS with OpenSSL. OpenSSL
appears to require the same pointer on a write that follows a retry
(CURLE_AGAIN) as discussed here:

http://stackoverflow.com/questions/2997218/why-am-i-getting-error1409f07fssl-routinesssl3-write-pending-bad-write-retr
curl.1: mention quoting in the URL section

and separate the example URLs with newlines
Implement public key pinning

Option --pinnedpubkey takes a path to a public key in DER format
and only connect if it matches (currently only implemented with
OpenSSL).

Extract a public RSA key from a website like so:
openssl s_client -connect google.com:443 2>&1 < /dev/null | \
sed -n '/-----BEGIN/,/-----END/p' | openssl x509 -noout -pubkey \
| openssl rsa -pubin -outform DER > google.com.der