Mail improvements: - Implement new config option in mail-section "ignore_alternatives" to ignore alternatives in a multipart/alternative mail. The *last* text/plain part of the *first* multipart/alternative is used as the message, if ignore_alternatives is set all other alternative parts of the first multipart/alternative that contained a text/plain part are ignored. Other multipart/alternative or other multipart are attached as before. This fixes [SF#959811] "Multipart/alternative handling considered bad". Note that this also changes which text/plain part is attached as the message if there are several text/plain parts in a multipart: Previously the *first* text/plain would be attached. Now we attach the *last* one, this is more in line with rfc 2046, sec. 5.1.4. according to Philipp Gortan. - Fix bug in attachment of text parts: If there are multiple text/plain parts in a nested multipart, the previous code would attach the multipart serialisation instead of the text/plain serialisation as a file to the issue in some cases. - Add regression tests for the new config-option and bug-fixes above.

<tal:block metal:use-macro="templates/page/macros/icing">
<title metal:fill-slot="head_title" i18n:translate="">List of classes - <span
 i18n:name="tracker" tal:replace="config/TRACKER_NAME" /></title>
<span metal:fill-slot="body_title" tal:omit-tag="python:1"
 i18n:translate="">List of classes</span>
<td class="content" metal:fill-slot="content">
<table class="classlist">

<tal:block tal:repeat="cl db/classes">
 <tr>
  <th class="header" colspan="2" align="left">
   <a tal:attributes="href string:${cl/classname}"
      tal:content="python:cl.classname.capitalize()">classname</a>
  </th>
 </tr>
 <tr tal:repeat="prop cl/properties">
  <th tal:content="prop/_name">name</th>
  <td tal:content="prop/_prop">type</td>
 </tr>
</tal:block>

</table>
</td>

</tal:block>