Upgrade to chartjs 2.0.2

[mcmoe]

Instead of forcing the bower dependency to chartjs 1.x.x, I've updated the code to match the latest API changes introduced in the chartjs 2.0 release. I've also enriched the demo with the eight different chart types. While doing so, I found it reasonable to allow declaration of multiple colors.

Extra:

• Support for shadow dom (div wrapper needed on chartjs-element to avoid chartjs error on resize when getting canvas parent)

Resolves issue #4

[googlebot]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

:memo: Please visit https://cla.developers.google.com/ to sign.

Once you've signed, please reply here (e.g. I signed it!) and we'll verify. Thanks.

---

• If you've already signed a CLA, it's possible we don't have your GitHub username or you're using a different email address. Check your existing CLA data and verify that your email is set on your git commits.
• If you signed the CLA as a corporation, please let us know the company's name.

[googlebot]

CLAs look good, thanks!