added basic/digest support option

[cvasilak]

done for AGIOS-255

the functionality is exercised in the HttpAuthenticationTests test case class where the different http/digest options are executed plus a test case with where a protection space is used and assigned to the NSURLSession.defaultConfiguration() (without the need to pass any credential object)

besides the tests, a demo app exerting basic/digest has also been created to demonstrate and can be found here

[corinnekrych]

As we don't stub http request we can remove this import

[corinnekrych]

update readme with:

• basic/digest support in the introduction paragraph
• let's add some basic/digest usage in https://github.com/cvasilak/aerogear-ios-http/tree/AGIOS-255#example-usage
  2 examples like with passing cred on each request vs. using credential storage

+1 to merge apart from small comments

[cvasilak]

@corinnekrych have updated based on your feedback

[corinnekrych]

For the test i'd add more test with httpstub instead of having all test "integration" like going to httpbin.org
But we can do that in separate PR.

+1 to merge

[cvasilak]

thank you @corinnekrych have updated

[abstractj]

On it....

[abstractj]

@cvasilak I'm looking at the sources, due to my poor skills on swift lemme ask. Is HTTPS enforced?

Not a deal breaker to merge this PR, but I would like to know before.

[abstractj]

@corinnekrych I can PR that, but I think we should provide examples with HTTPS by default.

Let me know where can I help.

[cvasilak]

@abstractj thank you for your feedback

not enforced the user can use either HTTP/HTTPS when constructing the request. For that reason have added an advisory in the javadoc for each function that HTTPS is preferred if credential is passed, and have updated auth tests to use HTTPS by default for that reason.

thanks again

[corinnekrych]

+1 for extra readme info