Fix for Hosts who don't support SHA2, GCM or PKCS5.pbkdf2_hmac

Some Hosts have Compiled Ruby against older Versions of OpenSSL, rendering SHA2, GCM and OpenSSL::PKCS5.pbkdf2_hmac useless.

This fixes it and also incorporates a safer Password checking routine, as seen on http://www.ruby-doc.org/stdlib-2.0/libdoc/openssl/rdoc/OpenSSL/PKCS5.html