Omaha Hold'em

[cryptorrivem]

I'd like to add the Omaha Hold'em rules to this library (I've been using the standard and works hells good).

Looking at how rules are set up, I was thinking on running all combinations of 2 from the hand cards and 3 from the table, but that might not be that performant.

Do you think there's a better approach for this @goldfire ?

Thanks in advance

[cryptorrivem]

I created PR #29 with this approach. Added some tests as well but haven't documented it yet.