inherit group from running thread, or create a new one -- make it harder to re-use canceled groups;
group is now non-optional;
tuned signature;
replaced low-level interrupts by group cancel operation;
misc tuning;
theory MicroJava
imports
"J/JTypeSafe"
"J/Example"
"J/JListExample"
"JVM/JVMListExample"
"JVM/JVMDefensive"
"BV/LBVJVM"
"BV/BVNoTypeError"
"BV/BVExample"
"Comp/CorrComp"
"Comp/CorrCompTp"
begin
end