Remove unused server trace stuff

de.prob.core/src/de/prob/core/Animator.java

de.prob.core/src/de/prob/core/IConnectionProvider.java

de.prob.core/src/de/prob/core/ITrace.java

de.prob.core/src/de/prob/core/internal/AnimatorImpl.java

de.prob.core/src/de/prob/core/internal/Message.java

...core/src/de/prob/core/internal/ServerTraceConnection.java

de.prob.core/src/de/prob/core/internal/Trace.java

...re/src/de/prob/core/internal/TraceConnectionProvider.java