[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/cpp_static_runme.php

@@ -0,0 +1,14 @@
+<?php
+
+require "tests.php";
+require "cpp_static.php";
+
+// New functions
+check::functions(array(staticfunctiontest_static_func,staticfunctiontest_static_func_2,staticfunctiontest_static_func_3,is_python_builtin));
+// New classes
+check::classes(array(StaticMemberTest,StaticFunctionTest,cpp_static,StaticBase,StaticDerived));
+// New vars
+check::globals(array(staticmembertest_static_int,staticbase_statty,staticderived_statty));
+
+check::done();
+?>