Hello, thank you very much to for sharing this directive, it's very useful. However I have the following issue: I have included [charts.js v2.0](https://github.com/nnnick/Chart.js/blob/v2.0-dev/dist/Chart.min.js) and then the directive and I get this error `Error: chart[chartType] is not a function` Any idea why the function `Chart.Line()` (or whatever) is not defined?