[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_frob_runme.php

@@ -0,0 +1,19 @@
+<?php
+
+require "tests.php";
+require "director_frob.php";
+
+// No new functions
+check::functions(array(alpha_abs_method,bravo_abs_method,charlie_abs_method,ops_opint,ops_opintstarstarconst,ops_opintamp,ops_opintstar,ops_opconstintintstar,prims_ull,prims_callull,corecallbacks_on3dengineredrawn,corecallbacks_on3dengineredrawn2));
+// No new classes
+check::classes(array(Alpha,Bravo,Charlie,Delta,Ops,Prims,corePoint3d,coreCallbacks_On3dEngineRedrawnData,coreCallbacksOn3dEngineRedrawnData,coreCallbacks));
+// now new vars
+check::globals(array(corecallbacks_on3dengineredrawndata__eye,corecallbacks_on3dengineredrawndata__at,corecallbackson3dengineredrawndata__eye,corecallbackson3dengineredrawndata__at));
+
+$foo = new Bravo();
+$s = $foo->abs_method();
+
+check::equal($s, "Bravo::abs_method()", "s failed");
+
+check::done();
+?>