Optionally return Action when doing Droplet action

Methods in Droplet than perform Droplet actions return dicts. The dicts
represent actions. Some may want these methods to return Actions instead
of raw dictionaries.

An optional paramater of return_dict was added to all methods that
perform Droplet actions. When set to false, an Action object is returned
instead of a dict.

Tests were added for when the Droplet methods return Action.