TimeLineWithFocusChart with dynamic axis

This commit fixes #495

Compare with lineWithFocusChart. Allows for adjustable tickFormat for specific focuses.
```
chart.xTickFormat.re(function (data) {
    range = d3.extent(d3.merge(data.map(function(d) { return d.values })).map(function(d) { return d.x }).concat([]));
    return function (d) {
    if((range[1] - range[0]) > day)
        return dateFormat(new Date(d));
    else
        return timeFormat(new Date(d));
    }
});
```