Fixed download issues.

All graphics download, font looks right, y,x, and legend labels are there in downloads. 
`chart.font_size + " '" + chart.font + "'"` appears in many places throughout, and if we need to change this later, it will be a pain to do it for all of them.

I wonder if you could set variables like:

```javascript
var chart.font_style = "font: " + chart.font_size + " '" + chart.font + " ' "
```
so on this line (and many others) you can write:

```javascript
.style("font", chart.font_style)
```