Improve trade logic

[galcohensius]

Currently, players can make a very weak trades, giving an opponent a monopoly while getting a "monopoly" of utilities
For example from the log:

Trade: Bob gives ['F2 Ventnor Avenue'], receives ['U2 Waterworks'] from Alice, Bob received price difference compensation $110 from Alice roll [1, 2]=3, goes to: U2 Waterworks, own property

• The minimal fix is to not allow Utilities trade vs "real" properties trade.

• The best fix is first separate the trade logic from the Player class and then experimenting different approaches and implement a new class of "smartPlayer"