Refactored NumericAttributeBinData out of ChartUtils and into its own class in weka.core.stats

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10930 e0a1b77d-ad91-4216-81b1-defd5f83fa92
Updated for changes to NumericAttributeBinData in distributedWekaBase

git-svn-id: https://svn.cms.waikato.ac.nz/svn/weka@10931 e0a1b77d-ad91-4216-81b1-defd5f83fa92