SOM example: enable mandatory concurrency (#450)

SOM requires mandatory concurrency to prevent hanging on 1-threaded configurations since this example has cross-graph dependencies

* SOM example: enable mandatory concurrency
* Add include & define NOMINMAX
* Improve comment wording

Signed-off-by: Kochin Ivan <kochin.ivan@intel.com>
Co-authored-by: Anton Potapov <anton.potapov@intel.com>