添加测试信息

src/bim-engine.css

@@ -20,4 +20,12 @@
     left: 50%;
     transform: translateX(-50%);
     z-index: 100;
-}
+}
+
+/* 构造树按钮 */
+.bim-construct-tree-btn {
+    position: absolute;
+    top: 20px;
+    left: 20px !important;
+    z-index: 100;
+}