auto-check just uploaded attachments

This may make it easier to eg, Insert Links after dropping in a lot of
files.

templates/editpage.tmpl

@@ -44,7 +44,7 @@ $(function () { $('#fileupload').fileupload(); }); // initialize upload widget
 </script> 
 <script id="template-download" type="text/x-jquery-tmpl"> 
     <tr class="template-download{{if error}} ui-state-error{{/if}}">
-        <td><input type="checkbox" name="attachment_select" value="${name}" />${name}</td>
+        <td><input type="checkbox" checked name="attachment_select" value="${name}" />${name}</td>
         <td>${humansize}</td>
         {{if error}}
         <td class="error" colspan="2">failed!</td>