tell people to stop using this where possible (pyca#759)

* tell people to stop using this where possible

* links require actual linking

* bolding

Author: reaperhulk

README.rst

@@ -14,8 +14,11 @@ pyOpenSSL -- A Python wrapper around the OpenSSL library
    :target: https://codecov.io/github/pyca/pyopenssl
    :alt: Test coverage
 
+**Note:** The Python Cryptographic Authority **strongly suggests** the use of `pyca/cryptography`_
+where possible. If you are using pyOpenSSL for anything other than making a TLS connection 
+**you should move to cryptography and drop your pyOpenSSL dependency**.
 
-High-level wrapper around a subset of the OpenSSL library.  Includes
+High-level wrapper around a subset of the OpenSSL library. Includes
 
 * ``SSL.Connection`` objects, wrapping the methods of Python's portable sockets
 * Callbacks written in Python
@@ -41,3 +44,4 @@ You can also join ``#cryptography-dev`` on Freenode to ask questions or get invo
 .. _`issue tracker`: https://github.com/pyca/pyopenssl/issues
 .. _cryptography-dev: https://mail.python.org/mailman/listinfo/cryptography-dev
 .. _GitHub: https://github.com/pyca/pyopenssl
+.. _`pyca/cryptography`: https://github.com/pyca/cryptography