所有页面的网页标题和页内标题区分开；搜索页允许查询空字符串（列出所有）

bookshelfplus-frontend/views/index.html

@@ -7,7 +7,7 @@
     <%- include("./component/navbar.html"); %>
     <div class="main">
         <div class="siteTitle">
-            <h1>书栖网</h1>
+            <h1><%=headText%></h1>
         </div>
         <%- include("./component/searchbox.html"); %>
         <div class="sloganBox">