Fix XHTML Doxygen docs inconsistencies

doc/footer.html

@@ -1,6 +1,7 @@
         </div>
         <div id="footer-container">
             <div id="footer">
+                CSFML is licensed under the terms and conditions of the <a href="https://www.sfml-dev.org/license.php">zlib/png license</a>.<br />
                 Copyright &copy; Laurent Gomila &nbsp;::&nbsp;
                 Documentation generated by <a href="https://www.doxygen.nl/" title="doxygen website">doxygen</a> &nbsp;::&nbsp;
             </div>

doc/header.html

@@ -2,14 +2,14 @@
 <html xmlns="http://www.w3.org/1999/xhtml">
     <head>
         <title>CSFML - C binding of the Simple and Fast Multimedia Library</title>
-        <meta http-equiv="Content-Type" content="text/html;"/>
-        <meta charset="utf-8"/>
+        <meta http-equiv="Content-Type" content="text/html;charset=UTF-8" />
         <!--<link rel='stylesheet' type='text/css' href="http://fonts.googleapis.com/css?family=Ubuntu:400,700,400italic"/>-->
         <link rel="stylesheet" type="text/css" href="doxygen.css" title="default" media="screen,print" />
         <script type="text/javascript" src="jquery.js"></script>
         <script type="text/javascript" src="dynsections.js"></script>
         <link rel="stylesheet" type="text/css" href="search/search.css" />
-        <link rel="stylesheet" type="text/css" href="searchOverrides.css" />        <script type="text/javascript" src="search/searchdata.js"></script>
+        <link rel="stylesheet" type="text/css" href="searchOverrides.css" />
+        <script type="text/javascript" src="search/searchdata.js"></script>
         <script type="text/javascript" src="search/search.js"></script>
         <script type="text/javascript">
         /* @license magnet:?xt=urn:btih:d3d9a9a6595521f9666a5e94cc830dab83b65699&amp;dn=expat.txt MIT */
@@ -24,3 +24,4 @@
             </div>
         </div>
         <div id="content">
+            <div>