Verify that the server's SSL certificate isn't blacklisted.

Note: This requires a new class, unfortunately. Previously we were using the nice shortcut `sendAsynchronousRequest:queue:completionHandler` but since we now need to implement NSURLConnection's delegate functions we now need to handle the lifecycle ourselves.
rm nslog
format braces on newline
Use SHA1 instead of MD5 for blacklist.
Tweak brace formatting
Use the non-deprecated callback
Merge pull request #34 from stripe/phil-ssl-blacklist

Verify that the server's SSL certificate isn't blacklisted.