Added units with Unitful.jl

src/Persefone.jl

src/core/input.jl

src/core/output.jl

src/crop/crops.jl

src/crop/farmplot.jl

src/nature/populations.jl

src/nature/species/skylark.jl

src/nature/species/wolpertinger.jl

src/nature/species/wyvern.jl

src/parameters.toml

src/world/landscape.jl