Sinatra support for hosting a minimal viewer

When testing remote data access with the viewer
file:// urls do not work.

This sets up a very minimal Sinatra app to serve an instance
of the viewer with the assets coming from Jammit.

The single view is views/debug.erb and is served from the root
Account#canEditAnnotation was returning undefined

Undefined isn't equivalent to false when passed to jquery toggleClass.  Instead it just toggles the class.
Only remove annotations if they aren't public

Before all notes were removed after a logout.  This preserves the public ones.
Read document slug from url and pass into DV.load

This way we won't have to update view whenever we want to load a
different document for testing.
Merge branch 'sinatraized' into tools_integration