feat: copyright info 文末添加版权等信息

Add a division to show copyright info
at the bottom of article automatically;
Hide the copyright info via putting
“original: false” to post’s front-matter.
添加一个方框展示文章版权声明的信息，在文章
顶部插入行 original: false 关闭。

Time format - http://momentjs.com/
MOxFIVE/M-Hexo-Blog#13

layout/_partial/post/nav.ejs

@@ -1,3 +1,15 @@
+<% if (post.original != false){ %>
+<div class="copyright">
+<p><span>本文标题:</span><a href="<%- url_for(post.path) %>"><%= post.title %></a></p>
+<p><span>文章作者:</span><a href="/" title="访问 <%=theme.author%> 的个人博客"><%=theme.author%></a></p>
+<p><span>发布时间:</span><%= post.date.format("YYYY年M月D日 - HH时MM分") %></p>
+<p><span>最后更新:</span><%= post.updated.format("YYYY年M月D日 - HH时MM分") %></p>
+<p><span>原始链接:</span><a href="<%- url_for(post.path) %>" title="<%= post.title %>"><%= post.permalink %></a></p>
+<p><span>许可协议:</span><i class="fa fa-creative-commons"></i> <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/3.0/cn/" title="中国大陆 (CC BY-NC-SA 3.0 CN)">"署名-非商用-相同方式共享 3.0"</a> 转载请保留以上信息。</p>
+</div>
+<% } else { %>
+<% } %>
+
 <% if (post.prev || post.next){ %>
 <nav id="article-nav">
   <% if (post.prev){ %>

source/css/_partial/article.styl

@@ -492,4 +492,28 @@ li:hover {
   .toc-link:hover {
   background: rgba(158, 188, 226, .21);
   }
+}
+.copyright {
+  width: 85%;
+  margin: 0px auto;
+  max-width: 45em;
+  word-break: break-all;
+  font-size: .93em;
+  line-height: 1.6em;
+  padding: .5em 1.8em;
+  background: rgba(255, 255, 255, .4)
+  border: 1px solid lightgray;
+  span {
+    color: #B5B5B5;
+    font-weight: bold;
+    margin-right: 1em;
+  }
+  a {
+    color: gray;
+    &:hover {
+      font-weight: bold;
+      color: #a3d2a3;
+      text-decoration: underline;
+    };
+  }
 }

source/css/_partial/mobile.styl

@@ -287,4 +287,8 @@
   a {
     color: #767676;
   }
+}
+.copyright {
+  width: 90%;
+  padding: .5em 1.3em;
 }