Download CSV breaks for '#' chars in Firefox

[aarose]

To reproduce:

1. Open Firefox
2. Go to http://jsfiddle.net/cqjvD/1069/ (or any export-csv enabled chart with a series that has the "#" character in the name)
3. Click "Download CSV" from the drop-down menu
4. Examine the CSV - the data is blank

Source:

The source of this issue seems to be in Highcharts.Chart.prototype.downloadCSV, when passing 'data:text/csv,' + csv.replace(/\n/g, '%0A'), as the href param.

Proposed solution:

Add .replace(/#/g, '%23') to encode the "#" character. Encoding the string could also be passed off to a new function that could encode all the special characters at once, not just newlines and "#".