[feature] make examples more useful

[elliottneilclark]

Exmple binaries show how to use the code, but they don't allow much input. We should clean up the input and output handling to make them better showcases.

TODO

• game_simulate.rs should be called monte carlo simulation since we have multiple now
• game_simulate should take in different hands via command line or std-in and then run the monte-carlo simulation
• agent_battle should report stats along the way.
• agent_battle should allow changing some things about the agents competing (number of agents, etc)