Re-introduce support for Channels.

I didn't think they were that important, really.

Change-Id: I3b9d2aa76702b764d95bce2cccc0e6a56856b4c9
Reviewed-on: http://gerrit.dmdirc.com/3468
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager

src/com/dmdirc/actions/CoreActionComponent.java

@@ -686,7 +686,7 @@ public enum CoreActionComponent implements ActionComponent {
         @Override
         public Object get(final Object arg) {
             // TODO: This should understand unset notifications
-            return ((Query) arg).getNotification().orNull();
+            return ((Query) arg).getNotification().or(Colour.BLACK);
         }
 
         @Override
@@ -734,7 +734,7 @@ public enum CoreActionComponent implements ActionComponent {
         @Override
         public Object get(final Object arg) {
             // TODO: This should understand unset notifications
-            return ((FrameContainer) arg).getNotification().orNull();
+            return ((FrameContainer) arg).getNotification().or(Colour.BLACK);
         }
 
         @Override

src/com/dmdirc/ui/WindowManager.java

@@ -190,7 +190,6 @@ public class WindowManager {
         checkNotNull(parent);
         checkArgument(isInHierarchy(parent));
         checkNotNull(child);
-        checkArgument(!isInHierarchy(child));
 
         parent.addChild(child);