update to parameter names and use of logical and.
Merge pull request #89 from Stavrakakis/master

ICS-46 : Post aggregation reintroduced and general Grouping refactor
using naming conventions in Dimension.  ChartGroup now working as event handler
fixed bug in Utils.keySelector that didn't respect a custom keyfunction. Added tests to ChartGroup
Dimension now creates filter functions, ChartGroup has more unit tests, as does dimension
Charts can be drawn without being inside a ChartGroup. Charts are drawn without init now; no need for a redraw() any more.
rebuild