Changed ChangeLog to text, added handler, added a custom function to determine the format.

M changelog_page.php

• Changed the changelog format to text.
• Changed to use a custom function to print on entry in the change log.

M core/custom_function_api.php

• (custom_function_default_changelog_print_issue): Default implementation for the changlog_print_issue() custom function.

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@2645 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9