- fixed xtract_spread() -- now just calls xtract_spectral_variance()
- fixed xtract_spread() -- now just calls xtract_spectral_variance()


eriser/LibXtract,caseybasichis/LibXtract,kecsap/LibXtract,jamiebullock/LibXtract,jamiebullock/LibXtract,kecsap/LibXtract,eriser/LibXtract,jamiebullock/LibXtract,caseybasichis/LibXtract,kecsap/LibXtract,eriser/LibXtract,caseybasichis/LibXtract