Add coverage statistics to HTML file for each source file

[neilskilling-overskilling]

It would be good to include the coverage statistics in the HTML generated for a single file and not just the summary page.

This would be the Function Coverage, Line Coverage, Region Coverage and Branch Coverage values for that file as shown in the index.html report for that file. Perhaps shown next to the "Created At" line at the top of the file.

This means that you can just refresh that page to check that you have achieved the desired coverage level without having to back to the index page each time.