Issue with chart.zoom() for large ranges + issue with overdragging

c3 version: **0.4.10** (oh, the jsfidlde uses master. so master too)

I want to display some statistics from the last hour at first, but the chart has to be draggable outside this 1 hour range (I will load additional data on the `zoom.zoomend` event)

Currently, I set range for one day (24h) and the graph is zoomed nicely.
When I set range to one year (plase uncomment the '\* 365' part), graph doesn't zoom.

Another bug: keep dragging forward, even after you hit the boundary. Now before you can move the chart backwards, you have to keep dragging backwards the same amount you over-dragged.

**JSFiddle: http://jsfiddle.net/9chmvpog/**