API for getting coverage information from SB-COVER system

[Paul F. Dietz]

I would like to be able to get information from the SB-COVER system without having to decrypt the html files it produces. Specifically, I would like, for each covered file, the information printed at the end of the coverage report for that file: ok-of, all-of, and percent for expression and branch.

It would be acceptable to have this available in some readable internal form after printing the html files (which I could ignore).

The purpose of this change is to enable tracking of coverage changes in a project as part of continuous integration or nightly testing.