added help menu (nmake -f Makefile.msvc help)
added help menu (nmake -f Makefile.msvc help)

kimwalisch/primesieve,fredwang00/primesieve,tempbottle/primesieve,ZahidDev/primesieve,anatoliyrazin/primesieve,ZahidDev/primesieve,tempbottle/primesieve,anatoliyrazin/primesieve,kimwalisch/primesieve,anatoliyrazin/primesieve,tempbottle/primesieve,fredwang00/primesieve,kimwalisch/primesieve,ZahidDev/primesieve,fredwang00/primesieve