OPTICS and DBSCAN now use distance functions from the core of WEKA. More distance functions can be applied, and normalization of attributes can now be turned off. Removed database parameter.

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10839 e0a1b77d-ad91-4216-81b1-defd5f83fa92