remove HamiltonDeck.load_from_lay_file (August 1)

[rickwierenga]

I deprecated this because parsing lay files (deck files) relies on imported VENUS-resources, which are also deprecated due to incompleteness and incorrectness. See #172 and #170.

We could load them from rck files which we search on the system, but that's more work for a feature that is barely used. They are also likely to be incorrect definitions. Also, in the future it's unlikely we will be able to load venus resources from rck files because we will require more information than venus offers.

[rickwierenga]

1a99c49