Changes the behavior for the 404 error and allows the use of Super Object in Delphi XE or up

About the 404 error, I started a conversation in PR https://github.com/fabriciocolombo/delphi-rest-client-api/pull/24. This change was introduced in this PR and  caused some problems for me (I updated last week, was using an old version of the lib). 

I think the error handling should be the same for all HTTP errors. If will not raise an exception, has to be the same for other errors.

I don't like exceptions too, but I think is too late to change this right now. I'm using this lib in a bunch of places and I will have to refactor a lot of code if we decide to remove this "exception flow".

 What do you think?