Add support for Cobertura coverage files written by Java.
Add a test which uses the report from a Java run of Cobertura to calculate coverage.
In the documentation of CTEST_COVERAGE_COMMAND, give a sample .sh file to merge
the Cobertura .ser files and generate the XML report from the merged file.
The coverage.py tool writes out an XML that conforms to the Cobertura
Coverage tool standard. Rename the cmParsePythonCoverage files to
instead be cmParseCoberturaCoverage.