Added a proper mock session that gets used for mock players in unit tests. Allows verifying that certain packets made it to the IoSession (the stage right before sending it to the client)
Fixed bug where quests could be repeatedly finished
Fixed bug where ironman status wasn't checked when buying overstocked items
Fixed bug where selling multiple items at a time that weren't listed in a shop would not succeed
Fixed bug where shop restocking would sometimes interrupt if a shop stock item was in a null slot
GE should now favor the buy offer if it's newer than the paired sell offer (buyer gets GP back)
GE should now favor the sell offer if it's newer than the paired buy offer (buyer does NOT get gp back)
GE should now always award bot offers to the highest bidder