Fixed bug in XMLObjectFactory.

Bug occurs when attempting to use the addParameter method in
DiscreteParameterGenerator. An example has been added to frace.xml.
Merge pull request #149 from censlin/xmlFactoryBugFix

Prevent restriction to reflective setter method lookup only.

This code originally looked up setter methods only. This widens the search to practically any method, which may result in problems. For the moment this is not doing any harm and seeing as the XMLObjectFactory IoC container's life is limited, I see no harm in merging this at this current point in time.