implemented second part of task-card #11
fixed a few typos
fixed a javadoc bug in build file
Modified Files:
build.xml
src/java/de/fhworms/ztt/ox/campusdatarepository/Course.java
src/java/de/fhworms/ztt/ox/campusdatarepository/CourseCatalog.java
src/java/de/fhworms/ztt/ox/campusdatarepository/StudentCatalog.java
src_test/java/unit/de/fhworms/ztt/ox/campusdatarepository/CourseCatalogTest.java
