[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/grouping_runme.php

@@ -0,0 +1,22 @@
+<?php
+
+require "tests.php";
+require "grouping.php";
+
+check::functions(array("test1","test2","do_unary","negate"));
+check::equal(5,test1(5),"5==test1(5)");
+check::resource(test2(7),"_p_int","_p_int==test2(7)");
+check::globals(array(test3));
+
+//check::equal(37,test3_get(),'37==test3_get()');
+check::equal(37,check::get("test3"),'37==get(test3)');
+//test3_set(38);
+check::set(test3,38); 
+//check::equal(38,test3_get(),'38==test3_get() after test3_set(37)');
+check::equal(38,check::get(test3),'38==get(test3) after set(test)');
+
+check::equal(-5,negate(5),"-5==negate(5)");
+check::equal(7,do_unary(-7,NEGATE),"7=do_unary(-7,NEGATE)");
+
+check::done();
+?>