Using php_info_print_table_header() for "Foo: bar" looks odd and out of place,
because the whole line is colored. It is also questionable from a HTML
semantics point of view, because it does not described the columns that follow.
The use of this across extensions is inconsistent. It was part of the skeleton,
but ext/date or ext/json already use a regular row.
Add clean_module_functions() to clean functions which are registered by zend_register_functions().
The general logic of clean_module_functions() is consistent with clean_module_classes().
