Fix html generation errors for boolean options. Code was generating xhtml form for html4 output. In xhtml, Boolean attributes like 'disabled', 'required' are represented with a value that is the same as the attribute name. E.G. <input required="required" ...>. Html 5 (and 4) represents the same as <input required ...> . Recognize booleans in one of two ways: value is None value is the same as the attribute name Make html4 and xhtml variants of cgi_escape_attrs. Have input_htmlp4 and input_xhtml call the proper variant. Also set HTMLInputMixin property cgi_escape_atrs to select proper one similar to self.input definition. Then replace calls to cgi_escape_attr with self.cgi_escape_attrs to get correct output.

<!--
 This is the default body that is displayed when people visit the
 tracker. The tag below lists the currently open issues. You may
 replace it with a greeting message, or a different list of issues or
 whatever. It's a good idea to have the issues on the front page though
-->
<span tal:replace="structure python:db.issue.renderWith('index',
    sort=[('-', 'activity')], filter=['status'],
    columns=['activity','title','creator'],
    filterspec={'status':['1','2','4']})" />