Added in test that checks to see if you can delete a single connection with a connection attached.
Added two tests proving issue 3011. The tests create a connection between two objects and tries to delete the entities associated with the connection without disbanding the connection.
Pruned old code.
Created a new Connection by downcasting the entity associated with the connection
Changed the iterator so that it will return ConnectionEntityRefImpl objects.
Initialized connection to null.
Added if else statements checking the possible instance types of the iterator.
Merge pull request #26 from GERey/USERGRID-3011-delete-connections

Usergrid 3011 delete connections