From MageKing17 and me: Fix for Mantis 3128: Docking related crash - dock_list isn't initialized
This patch makes the copy constructor and the assignment operator of the object class private as it contains members that should not be copied.

git-svn-id: svn://svn.icculus.org/fs2open@11170 387891d4-d844-0410-90c0-e4c51a9137d3