Virtual fields cause the show view to error.

If a virtual field is configured for the show view of a model, the current view file raises a NoMethodError attempting to use the virtual field name as a method on the model.

This pull request fixes this by having the view file check for field value presence against the pretty_value when one is supplied by the user. As a side-effect, there is now an "#{option_name}_supplied?" method for every option declared on a field. These methods return true if the user has overridden that option, otherwise they return false.