Add CRL tests for the PB protocol, for checking client certificates

Also, add a heavily modified make_certs lib from OTP's test suite for
generating certificates via openssl. make_certs is used to generate a
bunch of certificates and CAs to test various scenarios.
uncomment counter code that was commented out just to make the test pass
Don't generate ECC certs by default, has issues with openssl <=1.0.0
Merge pull request #416 from basho/adt-pb-crl

Add CRL tests for the PB protocol, for checking client certificates