introduce code coverage measurement for Certification/QA

In order to understand that validity of our automated testing, we should have a way to measure its code coverage.

A industry standard practice is to use a tool that pre-compiles the code to be tested with a set of instrumentation points designed to trace if the code is executed through all logic branches.

After testing the results obtained for the executed instrumentation points are compared against all inserted ones, hence providing a percentage of path been covered.

There are several code coverage measurements available but the most used are function and condition coverage
http://en.wikipedia.org/wiki/Code_coverage

Here is a tool example used within ltp:
http://ltp.sourceforge.net/coverage/lcov.php

Code coverage measurements provide deterministic way to quantify improvements to test coverage and to identify areas of poor test coverage.