* Fixes a major bug where players can stack items into their backpack infinitely even if they get a message saying they can't.
* Fixes other minor issues and cleans up code.
* Adds `RaceFlag` to the `Race` object. This is `1 << RaceIndex`
* Replaces `RequiredRace` with `RequiredRaces` for items.
* Adds convenience flags for `RequiredRaces`
```cs
public const int AllowAllRaces = 0x7; // Race.Human.RaceFlag | Race.Elf.RaceFlag | Race.Gargoyle.RaceFlag
public const int AllowHumanOrElves = 0x3; // Race.Human.RaceFlag | Race.Elf.RaceFlag
public const int AllowElvesOnly = 0x2; // Race.Elf.RaceFlag
public const int AllowGargoylesOnly = 0x4; // Race.Gargoyle.RaceFlag
```
* Example usage on an item:
```cs
public override int RequiredRaces => Race.AllowHumanOrElves;
```
* Adds Wood and Stone armor material types
* Updates Woodland armor to Wood
* Adds proper messaging for race restrictions
* Adds gargoyle only for object properties
* Adds `CheckRace` functions for validating if a race or mobile can use the item:
```cs
bool CheckRace(Race race);
bool CheckRace(Mobile from, bool message = true);
```
* Adds save flag support (see `ElvenGlasses` for an example)
* Updates AOSAttributes so they are code genned
* Fixes embedded object support by adding an `IRawSerializable`
* Fixes various inconsistencies in serializing with codegen
