[PHP] Add support for PHP7.

PHP5's C extension API has changed substantially so you need to use
-php7 to specify you want PHP7 compatible wrappers.
Fixes https://github.com/swig/swig/issues/571

Examples/test-suite/php5/template_construct_runme.php

@@ -0,0 +1,11 @@
+<?php
+
+require "tests.php";
+require "template_construct.php";
+
+check::classes(array(Foo_int));
+$foo_int=new foo_int(3);
+check::is_a($foo_int,"foo_int","Made a foo_int");
+
+check::done();
+?>