Add statement, subroutine and branch details to cover.xml output

[otrosien]

First shot. The report structure has become too large to deeply analyze it in end-to-end test, so I opted to take it out. What's your take on it? I'd be willing to adopt it to your requirements.

[otrosien]

Here's how the results look like: https://github.com/otrosien/sonar-perl#sneak-preview