Improve handling for all-in actions

[CharlieHess]

When a player bets all their chips, these actions are still labeled as "bets" or "raises." It would be helpful to note that these are all-ins, and provide an "all-in" action.

[pstutes]

@CharlieHess Would it be better to call it Push (p) ? http://poker.wikia.com/wiki/Push

[CharlieHess]

@pstutes: All poker clients that I know of use the term all-in.

[tvb]

+1 on all-in also, besides a (B) Bet option perhaps there should be an (A) All-in option?

[rodrigoma]

I created a pull request to my implementation #58