Add state argument to delete

[JonathanLorimer]

This PR also includes diff changes from #65

All call sites of sessionStoreDelete have access to the state argument, and in my case I want to only clear the state for a specific authentication request (not all of them), therefore I need to identify which entry I am going to remove.

I could parameterize my entire session store by State but that is kind of clunky and doesn't allow me to simply define the session store once.

[JonathanLorimer]

@krdlab

[JonathanLorimer]

@krdlab I rebased, and fixed the failure on the example component. Ready for review again