Merge pull request #43 from p-push/ssl-gcrypt

Only initialize gcrypt if we are using an older gnutls that needs this.
Add suport for CURLINFO_CERTINFO and CURLOPT_CERTINFO.

This patch adds support for CURLINFO_CERTINFO (and CURLOPT_CERTINFO),
as well as documentation for them and a couple of minor documentation fixes.
These options appeared in libcurl 7.19.1.

The format of the returned information was chosen to be reasonably close
to the underlying libcurl data structure, while also allowing a
Python programmer to pass the cerificate info to dict() in order to get
a more convenient representation.

https://sourceforge.net/p/pycurl/patches/14/
Conditional compilation for CERTINFO bits
Use an ordinary DECREF
SSL certinfo test using github
wip on ssl