Move around some namespaces for documentation purposes.

Fix problems with building on clang 2.8.
Remove unneeded function for get_engine() and fix functor<> calls that take a Boxed_Value

unittests/functor_creation_test.cpp

@@ -8,9 +8,19 @@ int main()
   chai.eval("def func() { print(\"Hello World\"); } ");
 
   boost::function<void ()> f = chai.functor<void ()>("func");
-
   f();
 
-  return EXIT_SUCCESS;
+  if (chai.functor<std::string (int)>("to_string")(6) != "6")
+  {
+    return EXIT_FAILURE;
+  }
+
+  if (chai.functor<std::string (const chaiscript::Boxed_Value &)>("to_string")(chaiscript::var(6)) == "6")
+  {
+    return EXIT_SUCCESS;
+  } else {
+    return EXIT_FAILURE;
+  }
+
 
 }