Should not cache store on server side

[nwshane]

This module currently caches the redux store on the server side, which is illogical and caused a bug in my app that was hard to track down. Caching on the client side makes sense - the redux store should only be created on the initial app load, rather than on each separate page load. However, caching on the server side means that the first request to the server will create a new redux store, and then the server will reuse that same store for every subsequent request.

The module next-redux-wrapper caches on the client and not on the server, so I've switched to that for now. If there is some strong reason for caching on the server that I haven't realized, then it should at least be documented clearly in the README.