fix decode error and write some doc

SuperScriptViewer/templates/help.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+    <meta charset="utf-8">
+    <title>Super Script Viewer Help</title>
+</head>
+
+<body>
+<h1>Super Script Viewer Help</h1>
+<p>In this file, I will introduce how to use this viewer.</p>
+<br />
+<br />
+<!-- todo: finish this-->
+</body>
+
+</html>