wideConvert lets the serious errors pass through, use it in Execute

util/control/ErrorHandling.scala

@@ -7,10 +7,17 @@ object ErrorHandling
 {
 	def translate[T](msg: => String)(f: => T) =
 		try { f }
-		catch { case e => throw new TranslatedException(msg + e.toString, e) }
+		catch { case e: Exception => throw new TranslatedException(msg + e.toString, e) }
+
 	def wideConvert[T](f: => T): Either[Throwable, T] =
 		try { Right(f) }
-		catch { case e => Left(e) } // TODO: restrict type of e
+		catch
+		{
+			case ex @ (_: Exception | _: StackOverflowError) => Left(ex)
+			case err @ (_: ThreadDeath | _: VirtualMachineError) => throw err
+			case x => Left(x)
+		}
+
 	def convert[T](f: => T): Either[Exception, T] =
 		try { Right(f) }
 		catch { case e: Exception => Left(e) }