Author: Egon Willighagen <egonw@...>
Date: 2011-06-28 (Tue, 28 Jun 2011)
Updated so that the writer does not fill in the valency field in the atom block by default, and added an IO setting to trigger writing.
Also updated the unit test to set the setting, to trigger output of the
Signed-off-by: Rajarshi Guha <rajarshi.guha@...>