Don't generate a .php wrapper file by default

It's now only generated if something to put in it is specified via:

%pragma(php) include=...

or

%pragma(php) code=...

Examples/test-suite/php/enum_scope_template_runme.php

@@ -1,6 +1,5 @@
 <?php
 require "tests.php";
-require "enum_scope_template.php";
 
 check::functions(array("chops"));
 check::classes(array("enum_scope_template", "TreeInt"));