- Prevents a NullPointerException in ice4j's Connector#stop() which appears...

- Prevents a NullPointerException in ice4j's Connector#stop() which appears quite often with unknown side effects.
- Prevents a NullPointerException in ToolsMenu related to the Jitsi VideoBridge menu item which causes of long chain of other exceptions and, eventually, prevents the application from completing its startup.
- Moves the C source code of JNI PortAudio library from Jitsi/net.java.sip.communicator to libjitsi/org.jitsi. Removes a couple of Java method and C function implementations each of which repeats three times. Fixes possible cases of leaving native callback threads which have been attached to the JVM in undetermined states.