Merge pull request #90 from niksoper/master

Resizing chart width with window.
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.
pre review comments and updates
updated readme example
fixing broken tests post rebase, and a sneaky BubbleSeries bug
updating how scatter series matches d3 data by specifying keyFunction
updates for Nick's review comments
update to ColumnSeries to remove extra functions
refactor to ChartGroup tests, renamed crossfilter variable in Dimension, refactor to Chart.highlight()
changed equality comparison in Dimension
fix to assertions in ChartGroup tests
Merge pull request #92 from Stavrakakis/master

ICS-58: Implement ChartGroup, remove clutter from global namespace and general decoupling
Updated structure of tests
Moved ChartGroup tests into charts directory.
Pearson correlation calculation on raw inputs.