[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_basic_runme.php

@@ -0,0 +1,58 @@
+<?php
+
+require "tests.php";
+require "director_basic.php";
+
+// No new functions
+check::functions(array(foo_ping,foo_pong,foo_get_self,a_f,a_rg,a1_ff,myclass_method,myclass_vmethod,myclass_pmethod,myclass_cmethod,myclass_get_self,myclass_call_pmethod,myclasst_i_method));
+// No new classes
+check::classes(array(Foo,A,A1,Bar,MyClass,MyClassT_i));
+// now new vars
+check::globals(array(bar_x));
+
+class PhpFoo extends Foo {
+  function ping() {
+    return "PhpFoo::ping()";
+  }
+}
+
+$a = new PhpFoo();
+
+check::equal($a->ping(), "PhpFoo::ping()", "ping failed");
+
+check::equal($a->pong(), "Foo::pong();PhpFoo::ping()", "pong failed");
+
+$b = new Foo();
+
+check::equal($b->ping(), "Foo::ping()", "ping failed");
+
+check::equal($b->pong(), "Foo::pong();Foo::ping()", "pong failed");
+
+$a = new A1(1);
+
+check::equal($a->rg(2), 2, "rg failed");
+
+class PhpClass extends MyClass {
+  function vmethod($b) {
+    $b->x = $b->x + 31;
+    return $b;
+  }
+}
+
+$b = new Bar(3);
+$d = new MyClass();
+$c = new PhpClass();
+
+$cc = MyClass::get_self($c);
+$dd = MyClass::get_self($d);
+
+$bc = $cc->cmethod($b);
+$bd = $dd->cmethod($b);
+
+$cc->method($b);
+
+check::equal($bc->x, 34, "bc failed");
+check::equal($bd->x, 16, "bd failed");
+
+check::done();
+?>