Provide ability to disable SSL certificates check.

There are sometimes cases in business appliance where one really wants to disable SSL checks, for instance during integration with third party systems it is not always possible to force them to update certificates used for https. 

Unit test is provided under integration tests section using washington university host. I would suggest providing proper endpoint at jsoup.org for that and refactoring unit test. 

11.11
- refactored code to do checks before aggressifve cast to HTTPSUrlConnection
- added proper unit test

I think we should change this (and the rest) to something like setValidateSslCertificates. That clarifies what this does.

Can you also add jdoc as to when a user would want to enable or disable this.

Also add what the default (on) is.