Fix R Lib files and testcase failing due to new preprocessor checks

Fixes unknown preprocessor directive error introduced in #217
commit 255c929c56
These were probably intended as script comments using # when C/C++
comments using // or /* */ should have been used.

Examples/test-suite/r_overload_array.i

@@ -1,7 +1,8 @@
 %module r_overload_array
-%include "stl.i"
-# this tests the situation in which there is a scalar function
-# corresponding with a vector one
+
+%include <stl.i>
+// this tests the situation in which there is a scalar function
+// corresponding with a vector one
 
 %inline %{
 class Foo {