Stub out main frame class.

Author: gk-brown

sierra-previewer/src/main/java/org/httprpc/sierra/previewer/MainFrame.java

@@ -0,0 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.httprpc.sierra.previewer;
+
+public class MainFrame {
+    // TODO
+}

sierra-previewer/src/main/resources/org/httprpc/sierra/previewer/MainFrame.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!DOCTYPE column-panel SYSTEM "sierra.dtd">
+
+<column-panel>
+    <!-- TODO -->
+</column-panel>