Allow SimplerTimer to die.

Still needs some methods to be able to reap it, and it's children.

core/java/src/net/i2p/util/SimpleTimer.java

@@ -183,6 +183,8 @@ public class SimpleTimer {
                             }
                         }
                     }
+                } catch (ThreadDeath td) {
+                    return; // die
                 } catch (InterruptedException ie) {
                     // ignore
                 } catch (Throwable t) {