Added DuelOption.RAKE

Feature Requested by werwew19.

A RAKE (in poker) is a portion of the pot that is kept by the house.

In other words, a RAKE can be thought of as a tax, fee, or money sink.

So, it's a small fee for betting money.

The RAKE is a percentage.
This means that 5.0 = 5%

So for a bet of $100 each & two players, the winner would receive 95%
($190).

src/java/config.yml

@@ -105,7 +105,8 @@ defaultOptions:
     #### Duel Options ####
     allowRatedDuels: false # By default dueling can not be rated
     # default duel options to pass in. Example [rated,money=100]
-    defaultDuelOptions: []
+    # rake is a money sink: It's the percentage that the house keeps in poker.
+    defaultDuelOptions: [rake=0.0]
 
     # after a player rejects a duel, how long before they can be challenged again
     challengeInterval: 1800 # (seconds) 1800 = 30minutes