Bug fix (implementing TODO & avoid old already unsupported way of informing the opponent about suggestion to start game)
Going towards learning LegalPlayer switching sides on-fly.
1) + Enriched Move by conversion to old string format
2) + Legal Player can start new game now from start and make its side white
3) - lost ability for LegalPlayer to start from given position (it resets position to the initial one when forced to move)
Tests are backl to stable.

At this point our Legal Player can switch from initially BLACK to WHITE state.

However it cannot repeat the trick and start new games again yet.
Removed duplicated comment.