Added bingo card balancing!

Now it is possible to create BingoSync-style balanced bingo cards with the training dummy!

The new example json ("Example JSON (real games, balanced BingoSync-style generation)") contains examples on how to add new information to the training dummy JSON to make it happen.

To the main structure of the JSON:

- add a key "use_srl": true,

For each bingo goal in "bingo_entries", add the following keys:

- "tier": [integer between 0 and 24] - corresponds to the index of the list the goal is in on the original bingosync card

- "type1": [string] - first type in the list of "types" in the original bingosync card

- "type2": [string] - second type in the list of "types" in the original bingosync card

If use_srl is false (or absent) from the input JSON, the usual, non-balanced, random card generation will be used instead!