- Fixed off-by-one error when checking for obligatory skills
- If both wisdom and magic school must be offered in the same slot, magic
school will be correctly offered on next levelup
- Obligatory skill can now be proposed for upgrade
- Obligatory skills are now offered using hero class weight instead of
simple random
- If hero has multiple skills not available to his class game will
select random skill instead of first one
- Moved storage of random seed to server instead of mutable member
- Constructor of Identifier from integer is now explicit
- Lobby hero/town selection now uses Identifiers instead of int's
- Removed serialization workaround for hero portraits
- Added dummy objects for custom heroes portraits for ID resolver to use
- HeroInstance now stores portrait ID only in case of custom portrait
- Fixed loading of campaign heroes portraits on RoE maps
