Added a (CSS hidden) hr tag after each post.

html.c

@@ -2731,6 +2731,11 @@ xs_html *html_entry(snac *user, xs_dict *msg, int read_only,
         }
     }
 
+    /* add an invisible hr, to help differentiate between posts in text browsers */
+    xs_html_add(entry_top,
+        xs_html_sctag("hr",
+            xs_html_attr("style", "display: none")));
+
     return entry_top;
 }