correct answer logic fails with Jquery > 3

[jackkinsella]

I know this library comes recommended for an earlier version of jQuery, but I wanted to bring this issue up so as to save anyone else some head-scratching.

The issue is that the not function in Jquery changed its behaviour recently: https://github.com/jquery/jquery/issues/3147

This breaks the compareAnswers function.

[jackkinsella]

suggested fix in PR: https://github.com/jewlofthelotus/SlickQuiz/compare/master...jackkinsella:patch-1