SecureWithTLSSettings additions to the Haddock documentation

[taladar]

I started using the recent additions from my other pull requests. Since it took me a while to figure out how to use them for this relatively common purpose (common to people who want to use this at all) I figured it might be helpful to have my connection test code as an example in the docs.

I put it into the docs for the Host type so it isn't so overwhelming for people who just get started with the library. If you know a better place I am open to changes.

It is mostly just a dump of my test code so I am sure it could be improved, though it should be relatively self-explanatory.

If you decide not to merge my other open merge request (SASL EXTERNAL auth) you should replace the last line of the example with one of the other bind operations. They work as they usually do.

[supki]

Sorry for the late reply. (I somehow missed the notification email GitHub sent me.)

I think this kind of example code is great, but I'd like it better if it were a separate file in the examples directory which the user can run directly (once she figures out how to install the dependencies).