Adding coverage info

I'm putting a way to generate coverage info about the tests that I
ran. The python file is another project called gcovr, I'll setup
Drone.IO to run this and check if we had lines with something like
this expression: "{digits}+(,|\-{digits}+)". This will detected
that a file has more than one line not tested. This sample rule
will keep the coverage over 95%, I hope.