Entity form display

This sandbox project brings the Drupal 8 concept of Entity form modes and Entity form displays to Drupal 7.

It is based on Artusamak's Entity form modes sandbox project.

On top of that it adds the following features:

• An API for adding, updating and deleting entity form modes
• A user interface for managing entity form modes
• A user interface for configuring entity form displays. This reduces the functionality of the Manage fields page of entities and introduces a new Manage form display page (similar to how it is in Drupal 8)
• Support for extra fields (such as the node title)
• Support for field groups as provided by the Field Group module

The plan is to release this as a full project at some point but before that the following must happen:

• Coordinate with Artusamak
• Add test coverage
• Make entity form modes exportable using the API provided by the Chaos tools suite

Also nice to have:

• Integration with the Display Suite Forms module of the Display Suite package