Previously, client mods adding packet-sending scripts to the spawn area made clients send the associated packets as soon as they inputted their character name when joining a server using those mods. This made the clients either get disconnected for not replying to a handshake first, or it made them get kicked for sending object packets that are disallowed for players who are not logged in.
To fix this, LocalPlayer's hasFinishedCharGen() has been replaced with isLoggedIn(), because the former was already returning true when players inputted their names.
Whenever an item is added to or removed from the player's ContainerStore, that player sends a PlayerInventory packet with just that addition or removal.
This eliminates all the unnecessary packet spam related to oversized PlayerInventory packets that had existed in one form or another since the initial implementation of inventory sync in 1b259e2d33
Additionally, move booleans from BasePlayer to LocalPlayer when they are only needed on the client, and make the usage of the isReceivingQuickKeys boolean consistent with the new isReceivingInventory boolean by having them both in the processors of their associated packets.
For a long time, whenever a PlayerInventory packet was sent, it contained all the items in the player's inventory, because that's how Koncord originally implemented it and I always had too many other priorities to go back and rework it.
From now on, clients only send PlayerInventory packet with the one item added or removed, with the single exception being trading with merchants, where the entire inventory is still sent for the time being.
Players can no longer unilaterally use items on themselves in their inventory. When they try to use an item, they send a PlayerItemUse packet to the server with the item's details. A serverside script can then check the item and either send the packet back to make the item use go through or drop it.
Spell, potion, enchantment, creature, NPC, armor, book, clothing, miscellaneous and weapon record data can now be sent in a RecordDynamic packet. Additionally, the packets include data related to associated magical effects (for spells, potions and enchantments), data related to default inventory contents (for creatures and NPCs) and data related to body parts affected (for armor and clothing).
The server now has associated script functions for setting most of the details of the above, with the main exception being individual creature and NPC stats.
Records can either be created entirely from scratch or can use an existing record (set via the baseId variable) as a starting point for their values. In the latter case, only the values that are specifically set override the starting values. Creature and NPC records also have an inventoryBaseId that can be used on top of the baseId to base their inventories on another existing record.
The client's RecordHelper class has been heavily expanded to allow for the above mentioned functionality.
When players create spells, potions and enchantments as part of regular gameplay, they send RecordDynamic packets that provide the server with the complete details of the records that should be created. When they create enchantments, they also provide the server with armor, book, clothing and weapon records corresponding to the items they've enchanted.
This functionality added by this packet was originally supposed to be exclusive to the rewrite, but I've gone ahead and tried to provide it for the pre-rewrite in a way that can mostly be reused for the rewrite.
Prevents compiler warnings such as this:
```
/Users/Will/CLionProjects/OpenMW/apps/openmw/mwgui/windowbase.hpp:65:22: warning: 'onOpen' overrides a member function but is not marked 'override' [-Winconsistent-missing-override]
virtual void onOpen();
^
/Users/Will/CLionProjects/OpenMW/apps/openmw/mwgui/windowbase.hpp:38:22: note: overridden virtual function is here
virtual void onOpen() {}
^
```
