* cert signature validation for certificates subcommand + a test
* refactoring validation + adding in a check for making sure that the private key matches the certificate
* adding testing certs
* assertIsNone(x) -> assertEqual(None,x) to unbreak the py2.6 tests
* modifying test_verifu_renewable_cert_failure to hopefully appease python 3 test timeouts
* updating cryptography to be >=1.2 so that we can use verify
* removing unused, old testing certificate
* adding better error handling/logging
* adding test for IOError
* switching to a 2048 bit rsa key