added methods "+" and "-"; event: non-synchronized execution of handlers, based on synchronized snapshot;
added methods "+" and "-";
event: non-synchronized execution of handlers, based on synchronized snapshot;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle