Upgrade dependency to new version of Chart.js

[NateRedding]

There is a new pre-release version of Chart.js. It looks like they are changing the reference in bower.json to 'Chart.js' from 'nnnick-chartjs'. There are other plugins that reference using the new name as well, ie. https://github.com/Regaddi/Chart.StackedBar.js/blob/master/bower.json

Angles should be updated as well for consistency. (At least once Chart.js 1.0 is finalized.)

[DeepAnchor]

+1!! Woo, looks like nnick is back and he decided to add tooltip functionality!

[jmtt89]

ready, now angles work with CharJS Beta

[NateRedding]

In bower.json, you should refer to Chart.js using the identifier 'Chart.js' instead of 'chartjs'. With the 1.0 release, this seems to be the recommended Bower identifier as other projects that I know work closely with Chart.js refer to it this way.

If you use a different identifiers, people end up with two copies of Chart.js thanks to Bower not realizing they are the same project.

[LeleDev]

+1... fix it soon please

[jmelosegui]

👍 and Dup from #57