[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/director_detect_runme.php

@@ -0,0 +1,55 @@
+<?php
+
+require "tests.php";
+require "director_detect.php";
+
+// No new functions
+check::functions(array(foo_cloner,foo_get_value,foo_get_class,foo_just_do_it,bar_baseclass,bar_cloner,bar_get_value,bar_get_class,bar_just_do_it));
+// No new classes
+check::classes(array(A,Foo,Bar));
+// now new vars
+check::globals(array());
+
+class MyBar extends Bar {
+  function __construct($val = 2) {
+    parent::__construct();
+    $this->val = $val;
+  }
+
+  function get_value() {
+    $this->val = $this->val + 1;
+    return $this->val;
+  }
+
+  function get_class() {
+    $this->val = $this->val + 1;
+    return new A();
+  }
+
+  function just_do_it() {
+    $this->val = $this->val + 1;
+  }
+
+  /* clone is a reserved keyword */
+  function clone_() {
+    return new MyBar($this->val);
+  }
+}
+
+$b = new MyBar();
+
+$f = $b->baseclass();
+
+$v = $f->get_value();
+$a = $f->get_class();
+$f->just_do_it();
+
+$c = $b->clone_();
+$vc = $c->get_value();
+
+check::equal($v, 3, "f: Bad virtual detection");
+check::equal($b->val, 5, "b: Bad virtual detection");
+check::equal($vc, 6, "c: Bad virtual detection");
+
+check::done();
+?>