doc: add doxygen link to README.md
doc: add doxygen link to README.md

Signed-off-by: Thomas Ingleby <cea8b9d820e871fd22532c955ca84ff867a004a3@intel.com>

fieldhawker/upm,Propanu/upm,nitirohilla/upm,Propanu/upm,kissbac/upm,mircea/upm,intel-iot-devkit/upm,MakerCollider/upm,tylergibson/upm,kissbac/upm,afmckinney/upm,sasmita/upm,andreivasiliu2211/upm,skiselev/upm,noahchense/upm,GSmurf/upm,Propanu/upm,jontrulson/upm,pylbert/upm,ShawnHymel/upm,GSmurf/upm,0xD34D/upm,Vaghesh/upm,whbruce/upm,tylergibson/upm,arfoll/upm,afmckinney/upm,andreivasiliu2211/upm,yoyojacky/upm,MakerCollider/upm,mircea/upm,whbruce/upm,intel-iot-devkit/upm,arfoll/upm,rafaneri/upm,MakerCollider/upm,intel-iot-devkit/upm,tripzero/upm,izard/upm,Propanu/upm,sasmita/upm,Jon-ICS/upm,MakerCollider/upm,spitfire88/upm,rafaneri/upm,sasmita/upm,rafaneri/upm,skiselev/upm,arfoll/upm,pylbert/upm,yoyojacky/upm,skiselev/upm,spitfire88/upm,spitfire88/upm,malikabhi05/upm,stefan-andritoiu/upm,afmckinney/upm,g-vidal/upm,mircea/upm,g-vidal/upm,pylbert/upm,stefan-andritoiu/upm,stefan-andritoiu/upm,tripzero/upm,rafaneri/upm,arfoll/upm,Vaghesh/upm,Propanu/upm,jontrulson/upm,jontrulson/upm,stefan-andritoiu/upm,arfoll/upm,afmckinney/upm,ShawnHymel/upm,Jon-ICS/upm,GSmurf/upm,kissbac/upm,yoyojacky/upm,whbruce/upm,whbruce/upm,g-vidal/upm,spitfire88/upm,whbruce/upm,skiselev/upm,noahchense/upm,stefan-andritoiu/upm,stefan-andritoiu/upm,g-vidal/upm,srware/upm,afmckinney/upm,spitfire88/upm,yoyojacky/upm,ShawnHymel/upm,tripzero/upm,g-vidal/upm,intel-iot-devkit/upm,MakerCollider/upm,Jon-ICS/upm,malikabhi05/upm,nitirohilla/upm,pylbert/upm,0xD34D/upm,srware/upm,mircea/upm,0xD34D/upm,noahchense/upm,izard/upm,GSmurf/upm,tylergibson/upm,Jon-ICS/upm,andreivasiliu2211/upm,malikabhi05/upm,0xD34D/upm,yoyojacky/upm,sasmita/upm,malikabhi05/upm,Propanu/upm,srware/upm,nitirohilla/upm,kissbac/upm,Vaghesh/upm,noahchense/upm,intel-iot-devkit/upm,srware/upm,tripzero/upm,nitirohilla/upm,pylbert/upm,fieldhawker/upm,andreivasiliu2211/upm,srware/upm,fieldhawker/upm,sasmita/upm,rafaneri/upm,izard/upm,tripzero/upm,ShawnHymel/upm,tylergibson/upm,Vaghesh/upm,malikabhi05/upm,ShawnHymel/upm,tylergibson/upm,intel-iot-devkit/upm,malikabhi05/upm,jontrulson/upm,andreivasiliu2211/upm,kissbac/upm,g-vidal/upm,mircea/upm,fieldhawker/upm,Jon-ICS/upm,skiselev/upm,nitirohilla/upm,jontrulson/upm,pylbert/upm,skiselev/upm