Function.name not defined in IE

[remojansen]

This issue was reported by @endel on Gitter.

The issues in IE are caused because Function.name is not an standard in JS versions < ES6.

The issue takes place here.

The good news is that function name is only used to provide developer-friendly errors and it will be fine to use the following:

function getFunctionName(f: any) {
    return f.name ?  f.name : f.toString().match(/^function\s*([^\s(]+)/)[1];
}

We can add the above function to the Planner class as a private method and invoke the function here:

let constructorName = getFunctionName(func);

[remojansen]

Done by #302