Adding spec help for raised exceptions in app

Given that routing errors require a custom exceptions_app, I want to
lean on using that custom exceptions_app as much as possible.

This matcher will help tests convey the proper meaning of what each
expected exception is and how the exceptions_app will handle it.
Adding behavior for common objects display
Updating application exception handling

I wanted to have a uniform exception handler; Instead of having some
cases that were handled via the ApplicationController.rescue_from and
some that were handled via Application.config.exceptions_app