Thank you very much for a lot of contributions and feedbacks. v0.4.0 has been released now and change list is like this:

New options and APIs:

• tooltip.show and tooltip.hide API - #467 #509
• grid.lines.front option - #462
• axis.y.default and axis.y2.default option - #442
• oninit option - #502
• axis.x.extent option instead of axis.x.default - #512
• zoom.onzoomstart and zoom.onzoomend options for callback
• data and data.shown and data.values API - #626
• axis.y.tick.values, axis.y.tick.count and remove axis.y.ticks - #560
• zoom API - #610
• zoom.rescale option to rescale y/y2 when zooming - #559
• axis.x.tick.multiline option to support multiple lines tick text - #139 #670
• data.axes API

Removed options and APIs:

• pie.sort and donut.sort options
• data.get and data.getAsTarget API
• axis.x.default

Minor changes and bug fixes:

• Modify zerobased if axis.y.min/max specified - #454
• Modify to fix the boundary of x domain when zooming - #505
• Modify legend to use class for focus
• Modify to separate clips for chart and grid - #502
• Modify to generate c3.min.css by grunt - #543
• Modify step chart interpolation - #566
• Modify to support unicode in class names - #665
• Modify bindto to accept d3.selection object - #715
• Fix tooltip when single data point
• Fix axis.x.min and axis.x.max when 0 - #457
• Fix padding when scatter chart - #457
• Fix svg height when gauge - #470
• Fix axis width when display:none on init - #468
• Fix data label on stacked line/area chart - #482
• Fix data label position when brushed - #485
• Fix onclick on step chart - #489
• Fix axis.x.tick.values for timeseries - #408
• Fix class properties for IE8
• Fix bar width on subchart when brush - #497
• Fix tick text rotation with negative value - #501
• Fix legend position to be centered - #515
• Fix grid and region when arc tyle - #518
• Fix event rect when flow called - #520
• Fix connect_null to connectNull - #516 #81
• Fix select for arc - #523
• Fix min/max for Gauge chart - #536
• Fix axis.x.tick.centered on category axis - #539
• Fix gauge when resize called - #546
• Fix only one data with custom x - #548
• Fix click on negative bar on rotated axis - #561
• Fix onclick/onmouseover on bar chart - #390
• Fix mouse events when point.show = false - #575
• Fix inset legend height without legend.inset.step - #326
• Fix multiple click on step chart - #608
• Fix millisec date parsing - #607
• Fix edge of step chart on category axis - #566
• Fix mouse event for multiple xs - #663
• Fix memory reak to watch insertion of chart - #668
• Fix legend background for inset - #326
• Fix to resize gauge value text automatically - #661