Track and report code coverage for your package and (optionally) upload the
results to a coverage service like 'Codecov' <https://codecov.io> or
'Coveralls' <https://coveralls.io>. Code coverage is a measure of the amount of
code being exercised by a set of tests. It is an indirect measure of test
quality and completeness. This package is compatible with any testing
methodology or framework and tracks coverage of both R code and compiled
C/C++/FORTRAN code.