Reorganized Event hierarchy.
Game store info about it's board.
- Implemented GameHistoryService.
- Changed Event hierarchy according to REST needs.
- Changed way of starting game in SimpleGameplay (because of not initialized GameHistory, which produced NullPointerExceptions in GameRunner)
- Correction in Event enums
- Method getAction() removed in MissileDestroyed class (implemented in base class)
- Factory method toBoardDefinition() moved to GameRunner class
- Added info about initial players positions in Game interface.
Optional used in GameHistory interface according to recomendation of @Adebski
Post rebase commit.
Merge pull request #33 from artekorzel/feature/rest-gamehist-service

Feature/rest gamehist service