added protection for when no points are available
Handle when there are no points in a dataset
Merge pull request #271 from gregbacchus/master

Fixed bug where no points on the graph causes an error in HoverDetail
Fixed a bug: When re-rendering axis, the appropriate number of ticks were not re-computed.
Made Legend swatches have swatch color instead of background-color.
Merge remote-tracking branch 'upstream/master'