Added JaCoCo test coverage.
Implemented as ant target called 'coverage'.
Will generate coverage html report in test/reports/coverage.
Do not throw away *.class files.
But keep in classes/ directory.

Used for coverage report in Jenkins and Sonar.
Move classes to build/classes.
Converted engine.Adaptor from interface to abstract class. 
Removed RECURSIVE from CopyOptions, since no adaptors support it. 
Added recursiveCopy to FileUtils.
Merge pull request #1 from NLeSC/feature/jacoco

Add test code coverage ant target.
Merge branch 'develop' into feature/unnest_adaptors_1plusM_buildxml