fix directorout typemap for const std::string&. Adding warning about the new typemap, which is not thread safe

git-svn-id: https://swig.svn.sourceforge.net/svnroot/swig/trunk/SWIG@6872 626c5289-ae23-0410-ae9c-e8d60b6d4f22

Examples/test-suite/ruby/director_string_runme.rb

@@ -0,0 +1,18 @@
+require 'director_string'
+require 'test/unit'
+
+
+include Director_string
+
+
+class B < A
+
+ def initialize(some_string)
+  super(some_string)
+ end
+end
+
+
+b = B.new("hello")
+b.get_first
+b.get(0)