Fixes fever temperature not being reached

Conflicts:
	code/modules/organs/organ_external.dm
Adjusts the rate that infections deal toxin damage

Conflicts:
	code/modules/organs/organ_external.dm
Fixes icons not being updated for necrosis
Updates to gun targeting UI. Fixes #5710

Conflicts:
	code/_onclick/hud/human.dm
	code/modules/client/preferences_toggles.dm
fixes #4961
temporary fix for #4907
Cargo train update

- Adds sprites (thanks to Bishop)
- Adds order-able train cargo crates

Conflicts:
	code/datums/supplypacks.dm
	code/modules/vehicles/cargo_train.dm
	icons/obj/vehicles.dmi
Cargo train fixes

- Visual tweak for mobs on trolleys
- Fixed a teleportation bug when boarding trains from other trains
- Fixed a runtime involving on_click code