add complicated-demo
Added demo for histogram with gridlines (with powerful accessors)

The demo now takes generated height/weight data, clumps by age,
and passes that in to the bar renderer. The yAccessor then extracts
average height from the group.
histogramWithGridlines demo no longer has tick marks on x-axis
Added chartWithLegend jsFiddle demo.
Fix chartWithLegend demo.
add the git stats data for plottable
Adjust Y axis tick test.

Travis fails the test due to off-by-1.
Fix the data
Update styling for labels
Allow wider center column
Initial version of Plottable.js commit history chart
Add Scale.widenDomainOnData with jsdoc.
Add Scale.widenDomainOnData with jsdoc.
Update styling for labels
Update plottable.js, plottable.d.ts, and other build artefacts
Merge branch 'master' into gh-pages