Poker Server/Client UI Updates

Separated out the player tables, and added APIs to set/clear the
"current player" chevron and the "last action" label. At the end of a
round, the players cards are revealed while their phones dictate who
won.

Chevron and last action aren't made visible yet because the stubs don't
exist and I don't want to muck with the flow inside PokerTable without
going through it more carefully.