[XmlBeans-279] Add convenience XmlOptions setter methods with boolean arguments

http://issues.apache.org/jira/browse/XMLBEANS-279

Hey guys,
I've got a patch ready for the jira issue above, I think its a
improvement, but had some design questions I wanted to chat about.

In my patch I've added a method like
setSavePrettyPrint(boolean flag){
if(flag)
  return set( KEY );
else
  return checkAndRemove( KEY );
}

My questions are:
should methods like above be named:
savePrettyPrint(boolean flag)

Also, does/will it make sense to have similar convenience method for
methods that take parameters? For example,
setSavePrettyPrintIndent(boolean flag, int indent)
it doesn't really make sense to me, but I wanted to confirm.

Thanks,
-jacobd