[JRO] Update set-up feature

Since so much has been cut back in terms of setup, the integration test is much smaller, leaner.
[JRO] Require appropriate authorization classes

These are needed in several places so I'm placing them in main file
[JRO] Reload engine files in dummy

By default the engine doesn't get loaded on every request.

`config.reload_plugins = true` in the dev environment's config will allow for reloading on requests like in normal dev mode.
[JRO] Copying over features and getting specs back to passing

* small cosmetic changes to dummy layout
* re-prioritize routes in dummy routes
* old features and mailers added back in. def not passing
* no longer require permissions from ability spec - it's required in lib/thredded
* setup page object gets a lot leaner
Ignore tags
Upgrade cancan
[JRO] Route constraint

… Checks whether or not the engine needs to be set up.
[JRO] Search related classes re-added

These should probably be extracted to another gem/engine. See issue #2
[JRO] Get topics working

Lots to add and change to get it working, period.

TODO: integration tests back working
[JRO] Active users. I hate this.

See https://github.com/jayroh/thredded_gem/issues/1

This is a hot mess.
[JRO] Application controller updates

* Inherit from parent application App controller.
* Include all the damn helpers
* `messageboard` method added back in. Will need it.
* Explicitly define current_ability since CanCan Cannot guess it. CanCanCan't do it all, Can it.
[JRO] Clean setup controller

As previously noted, this is a bit leaner.
[JRO] Add helpers and misc partials

* The engine's application helper now does the job of passing along helper methods to the parent application. Things like route/path helpers now pass through
* Messageboard and Posts helpers should probably be in decorators and not helpers. See https://github.com/jayroh/thredded_gem/issues/3
* Add search, error msg and analytics partials.
[JRO] Use AR, not sql
[JRO] No need to reference Thredded namespace

Ruby will find the appropriate class since current class is namespaced within Thredded already.
[JRO] Add messageboard view and partial

TODO: Clean up index. See - https://github.com/jayroh/thredded_gem/issues/4