support Entity API exportables

WIP - exports should be fine - import needs to be done, but more overrides should be done in the storage class.

Actually, turns out features needed to be enabled - at least to get rid of all the constants, probably needs some rethinking, although it should be possible

Thanks for working on this!.

Personally I preffer to duplicate the code from features to avoid need to install both modules in order to export entities.

Yeah me too, I had features enabled by accident, that's why it was working initially, it's back to the drawing board I'm afraid.

This is working for me. Please confirm.

Added the automatically detection of fields attached to an entity.

Tested with rules (see #1923314: Integration with Rules).

Fixed dependency detection, rules doesn't allow fields.

Committed and Pushed to 7.x-2.x.

@dagmar - sorry for not getting back to this, but I can confirm the commit works fine. Tested it with a rule export and comes in fine, nice work!