constructor.name problematic use

[tcrespog]

Hi, I've noted that relying on constructor.name to verify the type of chart causes the plugin not to work when using code obfuscators or minimifiers. In this plunkr the problem is reproduced.

Maybe another way of checking the chart type could be used, or maybe the checking could be removed altogether.

[MaximeCouasnon]

The plugin is also broken in IE11. Please checkout #18 for a solution.

[goofballLogic]

Horrific client-side workaround:

var c = Chartist.Line.prototype.constructor;
Chartist.Line.prototype.constructor = function Line( container, data, options ) { 
    return c.call( this, container, data, options );
};