added class hierarchy for stopwords algorithms

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10978 e0a1b77d-ad91-4216-81b1-defd5f83fa92
turns word into lower case now before testing patterns

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10979 e0a1b77d-ad91-4216-81b1-defd5f83fa92