Merge pull request #398 from gballet/master

Data vailidity check
Add donut.radius.inner option
Fix conflict
Add donut.width and remove donut.radius.inner
Apply data.order to donut/pie chart
Use desc as the default of data.order
Introduce bar.width.max - #174
Support json and rows on flow api - #424
Use c3.js in bower - #429
Add axis.x/y/y2.tick.outer option - #441
Closes #451
Merge pull request #452 from unwiredbrain/patch-1

Closes #451
Fix mouse event bug on multiple xs - #453