Minor cleanup and use byte(b)/short(s)/float(p)

also add the following to position and normal in float case 

				const float *f = (const float *)(data_ + decFmt_.posoff);
				for (int i = 0; i < 3; i++)
					pos[i] = f[i] ;

				const float *f = (const float *)(data_ + decFmt_.nrmoff);
				for (int i = 0; i < 3; i++)
					nrm[i] = f[i] ;