Add warning and link to Climate Laboratory to all notebooks

Update README with deprecation notice and link to Climate Laboratory book

Remove specific xarray version -- the metpy problem was fixed

Replace all ramadda server instances with thredds

Rerender all notebooks with climlab 0.7.5

Update README with clearer instructions for setting up conda environment

Update and test all lectures for latest climlab

Update environment.yml for standalone usage

Give lecture numbers to Toy Transient Models Land-Ocean notes, renumber everything again.

Finish renumbering notebooks

Adjust lecture numbers to make room for CESM climate sensitivity notes

Hack to fix the diffusion model in final lecture

In-class additions and fixes to Land warming notes

Remove stand-alone notes on Byrne theory derivation

Finished (sort of) notes on land-ocean warming contrast