Patch by Sjoerd Mullender to placate /F:

Patch by Sjoerd Mullender to placate /F:

Fix leaking of instances by removing the elements variable that we
created on closing the parser.  The elements variable is now created
in the reset() method, so that the sequence close(); reset();
... works.
Also, add the name of the entity reference that wasn't found to the
error message.