Add ability to configure most of Sinatra's settings

This add's the ability to set most of Sinatra's settings through
Deas. This allows some customization of the Sinatra app but only
through Deas API. The main intent is to allow customization of
things like serving static files, supporting sessions and
changing paths to the public or views folder.
Merge pull request #3 from redding/jcr-configure-sinatra

Add ability to configure most of Sinatra's settings