Code coverage

[probert94]

As requested in angelozerr/angular-eclipse#27, the plugin should be able to show code coverage results of karam tests.
I had a quick look at it and it seems like we have the following possibilities:

• Use the json reporter, which creates a coverage.json file, containing all needed informations. Here is a documentation on the format.
• Use the Public API and use the karma-coverage in-memory reporter

Then we could take a look at EclEmma source code. EclEmma is a code coverage plugin for eclipse, which colors the codelines, depending on the coverage result.
So we could take this as a reference implementation of the view in Eclipse.