Update AccessPoint.java

Tolerate access point without server node

tools/model_generator/src/com/libiec61850/scl/model/AccessPoint.java

@@ -42,9 +42,7 @@ public class AccessPoint {
 
 		Node serverNode = ParserUtils.getChildNodeWithTag(apNode, "Server");
 		
-		if (serverNode == null)
-			throw new SclParserException(apNode, "AccessPoint has no server defined!");
-			
+		if (serverNode != null)
 	                this.server = new Server(serverNode, typeDeclarations);
 		
 	}