Added a new ctools content type plugin that allows adding single tree items that have been limited down.

* Moved settings for the limitation into a new entity_collection_style.
* Added minipanel support for the limited collections.
* Added submit postprocessing of settings within the entity_collection_style.

Lars Linnet authored Jan 20, 2013 and Fabian Sörqvist committed Jan 20, 2013

Issue #1888254 by lslinnet: Fixed Entity_collection().class.inc is being loaded as a ctools plugin due to file ending.