Fix ticket #591: reCaptcha always on the page.

1) move creating the "Add a comment" button into the comments.html.php
2) use $.get() to retrieve the comment add form

modules/comment/helpers/comment_theme.php

@@ -26,7 +26,6 @@ class comment_theme_Core {
   static function photo_bottom($theme) {
     $block = new Block;
     $block->css_id = "gComments";
-    $block->anchor = t("comments");
     $block->title = t("Comments");
 
     $view = new View("comments.html");
@@ -37,7 +36,6 @@ class comment_theme_Core {
       ->find_all();
 
     $block->content = $view;
-    $block->content .= comment::get_add_form($theme->item())->render("form.html");
     return $block;
   }
 }