More multiplayer fixes and casting effects — Andalia Steam update #351189

This patch addresses a few things that went broken in multiplayer during the recent patches: Farm plants now properly spawn on remote clients again. Workers again depart from their resource building after resource delivery. After the recent patch, they would often stay inside of the building indefinitely. The basic bug here also caused a number of other weird things. Now it's been fixed. Additionally there is a new feature now: I let myself be inspired by certain roleplaying games and added a magical circle effect around casters of spells during their casting animation. It doesn't only look nicer, it also makes it clearer to the player when a particular unit is casting something. Other than that, my current pipedream for Andalia is adding a sixth civilisation with a large number of unique mechanics to it: The Necrop...