pipe the sinatra call settings to the view handler via `app_settings`

This exposes the sinatra call's settings via the `app_settings`
method on a view handler.  This is needed with the no singleton
version of Deas so that view handlers can access app configuration
values and settings.  Previously the singleton provided this access.
Merge pull request #52 from redding/kr-appsettings

pipe the sinatra call settings to the view handler via `app_settings`