Generate pin without M2Crypto python module

[TeunVR]

If you don't have M2Crypto installed you can use the following openssl commands to generate the pin (on OS X OpenSSL 0.9.8y 5 Feb 2013):

openssl x509 -in certificate.cer -inform DER -outform DER -noout -pubkey | openssl rsa -pubin -outform DER | openssl sha1 -hex

[DirtyJerz]

This should be included in the README. Installed M2Crypto (and swig, and python-dev) and made it work but this could have saved me like 5 minutes. :P