Authenticode

Add support for parsing X509 certificates from Authenticode signatures.
I was going to go down this route but the problem is that the ASN1_TIME structure can store more dates than a time_t. See this (specifically the last paragraph) for more information:

http://comments.gmane.org/gmane.comp.encryption.openssl.devel/10524

I'd have to keep the ASN1_TIME structure as is and then have the date() you are describing convert to time_t, and then call X509_cmp_time() with them both as arguments. By keeping the ASN1_TIME structure around we can also do things like "pe.signatures[i].has_expired()" which will call X509_cmp_time(notAfter, NULL) internally.

Let me see what I can come up with allowing us to do these kinds of things.