Add gRPC API for multicast service.

Change-Id: I003b982145c788e74c39f525122d58f3204b1c0e
diff --git a/incubator/pom.xml b/incubator/pom.xml
index a8c7f9d..5dbd8b4 100644
--- a/incubator/pom.xml
+++ b/incubator/pom.xml
@@ -38,6 +38,9 @@
         <module>protobuf</module>
         <module>rpc</module>
         <module>rpc-grpc</module>
+        <module>rpc-nb</module>
+        <module>protobuf-nb</module>
+        <module>grpc</module>
     </modules>
 
     <dependencies>