Add (selective) "reusability functionality" to content boxes entities

[frega]

This is a feature request for functionality similar to the fieldable panel panes "reusability".

1. As a sitebuilder i want to configure if a bundle can have reusability functionality (eck behavior?)
2. As a sitebuilder i want to configure who may determine reusability of entity instances (permissions)
3. As a developer i want to ensure that if a reusable content box is added to a host entity, deleting the host entity does not delete the (embedded) content box entity.
4. As a sitebuilder i want to be able to create an administrative views of "reusable" entity instances
5. As an editor i want to have a simple interface to select reusable entities.
6. As an editor i want ot be able to distinguish between "local" and "shared" content boxes.

[axe312ger]

Very nice and useful ideas. Since we do not have and want a big bloated fancy module, I decided to separate your requirements into several modules.
Point 1,2,4 and 6 will go into the new eck_shared_entities module
Point 3 will end up in a module for "smart" entity deletion
Point 5 will end up in a module for a proper existing entity form for IEF

[frega]

<3

[axe312ger]

1,2,4 and 6 are now fulfilled via the eck_shared_entities module. Can you please review the module and code?
Also add further feature requests to the issue queue of that module.

My next goal is to find a solution for point 5.