Fix a index_unit_test misconfiguration that was causing all sorts of compile errors.
Suppress VC++ warning C4251, shared_ptr needs to have a dll-interface..., which is as irritating as ever.
Supply a line of code that got dropped by mistake during refactoring.
Suppress VC++ secure code warnings. All index_unit_test tests are now passing under VC++ 2012. On to GCC and older versions of VC++!