#1304 P25 Phase 1/2 decoder enhancements. (#1898)

* P25 Phase 2 now supports control channel decoding and decoder was enhanced to improve decodes.
* Radio reference site editor updated for phase 2 sites to allow user to select FDMA or TDMA control.
* Decode events are now minimized and de-duplicated.
* Fully parsing all phase 1/2 messages from the latest ICD.
* Vendor specific messaging recoveries (Moto & Harris).
* Patch group management enhancements with stale patch detection.
* Tuner editor now fully resets the min/max frequency values
* Default traffic channel count increased to 20 (from 3).
* ISSI roaming radio and talkgroup values now displayed and aliasable as fully qualified values (e.g. 1234(123.456.7890)
* Moto emergency alarm activation messaging support
* Expanded list of P25 encryption algorithms
* Message (bits) viewer enhanced for P25 phase 1 and phase 2
* IPV4 addresses and UDP ports no longer classified as user values - won't display in event views.
* New framework for describing message binary fields that should reduce overall memory footprint and enhance code readability

Co-authored-by: Dennis Sheirer <dsheirer@github.com>

src/main/java/io/github/dsheirer/controller/channel/ChannelProcessingManager.java

@@ -279,7 +279,7 @@ public class ChannelProcessingManager implements Listener<ChannelEvent>
                 break;
             case REQUEST_DISABLE:
             case NOTIFICATION_DELETE:
-                if(channel.isProcessing())
+                if(channel != null && channel.isProcessing())
                 {
                     try
                     {