lasso instructions refer to outdated script

[deeplycloudy]

The last step in https://github.com/deeplycloudy/lmatools/tree/master/examples/README.mdown refers to an old way of passing the arguments, instead of the new argparse version. Update these docs.

Also, if no filenames are provided it would make sense to default to using the standard path, instead of requiring the flag to look there. But this might not work for the GLM version of this script.