Implement better exception reporting.

[emlynwest]

Implement http://filp.github.io/whoops/demo/ for nice informative error reporting.

[emlynwest]

Thanks to @jamesarnold for this suggestion.

[WanWizard]

Done. Still need some templating, and a custom handler to report Application specific information.

[sagikazarmark]

I mention here my idea: it would be awesome if the dev could have an own route for any exeption (not only the basic HTTP Exceptions)

Generally something like `$handler->addException('MyException', 'route/to/handler/page').

It could generally make easier adding more basic exceptions to the core as well.

[sagikazarmark]

Worth taking a look:

https://github.com/brandonsavage/booboo

[sagikazarmark]

@stevewest @WanWizard what do you think about switching to booboo? It has been moved to the league and seems to be more decent AND more importantly actively developed.

[emlynwest]

If booboo is going to be better supported then I'd vote for switching to that. understand that @WanWizard has already integrated whoops and styled it so it's his call.

[sagikazarmark]

It is not a problem, as I am working on the official import of the PrettyPageFormatter for booboo. So it won't be a big change.