Update failure on saving an array which contains overlapping graphs.

[jamoore]

Currently the process of unloading already merged entities has a flaw that appears if the same (==) entity is contained in more than 2 calls to filter.filter().

This can be shown with the trivial:

  SomeEnum[] arr = new SomeEnum[3];
  arr[0] = new SomeEnum();
  arr[0].setValue( "test" );
  arr[1] = arr[0];
  arr[2] = arr[1];
  iUpdate.saveArray( arr );

[jmoore]

This was caused (closed in r697) by Details having too many responsibilities. As a persistence/security device, it was being deleted on unload, but its replacement member was there for internal book keeping. This responsibility has been moved to IObject.getGraphHolder().

[jmoore]

r698 contains a failing test. (See URoiTest#L33)