* AppContext: Add hasWrapper() method

* Shutdown:
    - Clear more resources in peer manager, netdb, stat manager,
      session key manager, naming service, tunnel dispatcher,
      OCMOSJ (result of testing with jvisualvm)
    - Don't call wrapper on shutdown (starting two threads) if we
      were started with runplain

core/java/src/net/i2p/stat/StatManager.java

@@ -57,6 +57,12 @@ public class StatManager {
             _statLog = new BufferedStatLog(context);
     }
     
+    /** @since 0.8.8 */
+    public void shutdown() {
+        _frequencyStats.clear();
+        _rateStats.clear();
+    }
+
     /** may be null */
     public StatLog getStatLog() { return _statLog; }
     public void setStatLog(StatLog log) {