Added a state NOT_READY to the exam
Modified Files:
src/java/de/fhworms/ztt/ox/core/Exam.java
src/java/de/fhworms/ztt/ox/examserver/RemoteExam.java
src_test/java/unit/de/fhworms/ztt/ox/core/ExamTest.java
src_test/java/unit/de/fhworms/ztt/ox/examserver/RemoteExamTest.java