Multiple RowSeries or ColumnSeries on one chart.
Fixed problems with axis ordering.
Using D3 range helpers to set position of RowSeries and ColumnSeries.
Merge branch 'tidyup' into remove-subseries

Conflicts:
	src/charts/Chart.js
Merge pull request #145 from niksoper/remove-subseries

Removal of sub-series from RowSeries and ColumnSeries