Revert "Created concept of entity_handle so we can move entities around in memory."

This reverts commit 9036af75fbdea031398cf4cbf247c6a966eeda51.
Revert "Revert "Created concept of entity_handle so we can move entities around in memory.""

This reverts commit 73317e58a54f5176f6ea082e8160ae07e39322d7.
Disable some code in the performance test that was causing visual C++ to generate a slow executable.  This only happened once introducing the handle concept.