Switch from Cobertura to Jacoco for test coverage
Cobertura can't handle Java 8: https://github.com/cobertura/cobertura/issues/176
We should switch to JaCoCo and start setting some test coverage goals.
Set test coverage to 40% (not enforced yet: some modules have even less)
Remove cobertura:cobertura in Jenkins
Generate Jacoco reports in Jenkins
Maven verify will generate Jacoco coverage