Add code coverage

[timmywil]

I am working on a project with a similar setup to this repo. I'm trying to use the traceur preprocessor for karma along with the istanbul coverage preprocessor and I ended up finding this issue on the istanbul repo. I'm opening an issue here so that...

1. There's a place to track automated coverage for the angular templating repo
2. I'll be notified once this repo has implemented a solution.

I imagine this problem will pop up a lot more when angular 2.0 is released. Thanks.

[jackwakefield]

I've created an instrumenter which can be used with karma-coverage called ismailia.

An example of the setup is here.