* 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/I2PAppContext.java

@@ -888,4 +888,12 @@ public class I2PAppContext {
     public InternalClientManager internalClientManager() {
         return null;
     }
+
+    /**
+     *  Is the wrapper present?
+     *  @since 0.8.8
+     */
+    public boolean hasWrapper() {
+        return System.getProperty("wrapper.version") != null;
+    }
 }