* Botany: Introduce shovel and spade into hydro\_tools
* Botany: Add shovel/spade (just removes plants)
* Botany: Add shovel/spade lathe recipes and make all botany lathe recipes accessible
* Botany: Add spade into Saltern
* Botany: Give Saltern a bucket for the botanist
* Botany: Plant produce can be composted for nutriment/etc.
* Botany: Bye-bye duplicated force update code, hello ForceUpdateByExternalCause
* Botany: Shovel identity crisis resolved (thanks Paul)
