References returned from methods should be deallocated and methods that
return those references should increment reference count to account for
that. These classes were writted before this system and didn't correctly
handle references. This patch addresses that.
`APlayer` and `ATrader` represented player and trader (`ShopVolume`)
with a single object instance. Such design, if used for all actors,
could have led to mutitute of problems rooted in need to find that
single object for any given native actor: we'd need to store
object-actor pairs separately and look through pairs lists, which is
hardly a sane design.
Now Acedia switches to a different design, where a single in-game entity
(i.e. actor) can have several interfaces referring to it. All equaly
valid. Refactoring `APlayer` and `ATrader` into `EPlayer` and `ETrader`
is a first step in that direction.
Refactors `User` to simply store persistent data, while making `APlayer`
represent a connecte playr with appropriate links to `User` and (in
future) his in-game pawn representation.
Anton Tarasenko