Final goal (of multiple PR's) is to remove all remaining pointers from
serializeable game state, and replace them with either identifiers or
with shared/unique pointers.
CGTownInstance::town and CGHeroInstance::type members have been removed.
Now this data is computed dynamically using subID member.
VLC entity of a town can now be accessed via following methods:
- getFactionID() returns ID of a faction
- getFaction() returns pointer to a faction
- getTown() returns pointer to a town
VLC entity of a hero can now be accessed via following methods:
- getHeroTypeID() returns ID of a hero
- getHeroClassID() returns ID of a hero class
- getHeroType() returns pointer to a hero
- getHeroClass() returns pointer to a hero class
