Changed the server Gemfile, made ruby debugger and pry available in test env
Handle errors when updating interactives.

Validate that an interactive's title is unique within a group and is not empty.
Validate that an interactive's path exists. Create a client side error
dialog to display interactive update errors.
Choose an interactive group when saving an interactive
A user should be able to make copies of previously saved interactives.
Disabled interactive save until after interactive has been updated
Makefile: import-interactives
Added missing interactive properties to rails model and presenter.

The following interactive properties, (fontScale, template and exports), where not defined
in the backend, rails, model and presenter for interactives. This will require a reload of
the couchdb with `rake app:import:build_interactives`.