added prtClusterSphericalKmeans.m
added prtClusterSphericalKmeans.m

jpalves/PRT,jpalves/PRT,jpalves/PRT,jpalves/PRT,jpalves/PRT,jpalves/PRT,covartech/PRT,covartech/PRT,covartech/PRT,covartech/PRT,covartech/PRT,covartech/PRT