Slab ocean in Docs + in Modules?

[navidcy]

After #42 the slab ocean example in the developer docs is rendered obsolete, right?

[navidcy]

Atm it's disabled from the docs because it was erroring.

NumericalEarth.jl/docs/make.jl

Line 45 in 9351533

# Example("EarthSystemModel interface", "slab_ocean", false),