make aidl interface strongly typed

app/src/main/aidl/com/geeksville/mesh/IMeshService.aidl

@@ -2,8 +2,7 @@
 package com.geeksville.mesh;
 
 // Declare any non-default types here with import statements
-// import com.geeksville.mesh.DataPacket;
-
+parcelable DataPacket;
 parcelable NodeInfo;
 
 /**
@@ -40,14 +39,14 @@ interface IMeshService {
     /**
     Get the IDs of everyone on the mesh.  You should also subscribe for NODE_CHANGE broadcasts.
     */
-    NodeInfo[] getNodes();
+    List<NodeInfo> getNodes();
 
     /// This method is only intended for use in our GUI, so the user can set radio options
     /// It returns a RadioConfig protobuf.
     byte []getRadioConfig();
 
     /// Return an list of MeshPacket protobuf (byte arrays) which were received while your client app was offline (recent messages only)
-    List getOldMessages();
+    List<DataPacket> getOldMessages();
 
     /// This method is only intended for use in our GUI, so the user can set radio options
     /// It sets a RadioConfig protobuf

app/src/main/java/com/geeksville/mesh/MainActivity.kt

@@ -596,7 +596,7 @@ class MainActivity : AppCompatActivity(), Logging,
             registerMeshReceiver()
 
             // Init our messages table with the service's record of past text messages
-            model.messagesState.messages.value = (service.oldMessages as List<DataPacket>).map {
+            model.messagesState.messages.value = service.oldMessages.map {
                 TextMessage(it)
             }
 

app/src/main/java/com/geeksville/mesh/service/MeshService.kt

@@ -1056,8 +1056,8 @@ class MeshService : Service(), Logging {
             this@MeshService.radioConfig = MeshProtos.RadioConfig.parseFrom(payload)
         }
 
-        override fun getNodes(): Array<NodeInfo> = toRemoteExceptions {
-            val r = nodeDBbyID.values.toTypedArray()
+        override fun getNodes(): MutableList<NodeInfo> = toRemoteExceptions {
+            val r = nodeDBbyID.values.toMutableList()
             info("in getOnline, count=${r.size}")
             // return arrayOf("+16508675309")
             r