Allow the setup of a custom ssl_context

[s0undt3ch]

Currently, unless one overrides server_runner there's no way to provide a diferent ssl_context.

Here's a patch the enables just that.

[s0undt3ch]

This paste is a sugestion to handle ssl errors(so we don't loose it):

 http://paste.pocoo.org/show/40106/

[s0undt3ch]

That last attachment catches all SSL.Error's and calls WSGIHandlerMixIn.wsgi_connection_drop(error).

If one want's to better take care of socket errors that's the method to override as stated in source. I can't seem to cleanly do it any other way.

Do note that errors do seem to reach the other end, maybe it's PyOpenSSL sending then because clients are aware of those errors, we aparently just cant customize the messages sent.

Anyway, at least like this one can implement minimal certificate client authentication.

[s0undt3ch]

more source code comments

[s0undt3ch]

more source code comments

[s0undt3ch]

This last patch, changes the way ssl_context is handled. It's now created based on the options passed by the user.