Updated date in Description.props

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@11341 e0a1b77d-ad91-4216-81b1-defd5f83fa92
Added stable sort methods to Instances class. ArffViewer now uses stable sort in Instances class when sorting columns, regardless of whether this is done via clicking the column header oder choosing from the pop-up menu.

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@11342 e0a1b77d-ad91-4216-81b1-defd5f83fa92