samples/openssl-hook: a library for embedding rats-tls into any program

[imlk0]

Please take a look at samples/openssl-hook/README.md

[houhuiting]

This pr has a great impact on my current task [rats-tls integrated librats] (https://github.com/inclavare-containers/rats-tls/issues/170), when I am almost done here, we will work together discuss how to merged