Excavator loses inventory when paused

Issue description

See title

Expected behavior

Not to lose the inventory

Reproduction steps

Have an excavator mine something, pause it, see the inventory become nothing.

Presumably this behavior is shared among all 3 types.

Game version

0.4.12

BTW, it also loses the inventory when being unassigned or told to move.

This is working as intended. Having to handle inventory of an excavator while it is not digging would get a bit messy and the excavator logic is already fairly complex.