Remove id attributes in wiki toolbar

[Jun Omae]

Wiki toolbar feature is generating the following for textarea.wikitext. The generated html has id attributes but wiki toolbars can be multiple, for example, when viewing ticket form if custom fields with wiki format are configured.

<div class="wikitoolbar">
  <a href="#" id="strong" title="Bold text: **Example**" tabindex="400"></a>
  <a href="#" id="em" title="Italic text: ''Example''" tabindex="400"></a>
  <a href="#" id="heading" title="Heading: == Example" tabindex="400"></a>
  <a href="#" id="link" title="Link: [http://www.example.com/ Example]" tabindex="400"></a>
  <a href="#" id="code" title="Code block: {{{ example }}}" tabindex="400"></a>
  <a href="#" id="hr" title="Horizontal rule: ----" tabindex="400"></a>
  <a href="#" id="np" title="New paragraph" tabindex="400"></a>
  <a href="#" id="br" title="Line break: \\" tabindex="400"></a>
  <a href="#" id="img" title="Image: [[Image()]]" tabindex="400"></a>
</div>

I think we should use class attributes rather than the id attributes.