Please implement a pure gamble run

[xg6636]

We have the gambling function in the current version, but there are a few limitations:

1. your gold must be more than 2.48 million, or it won’t gamble;
2. it can’t gamble to 0 gold, it stops gambling when gold is less than 500k.
3. the bot can’t use gold in the shared stash.

I think it’s a good idea to implement a pure gambling run which has no limitations like the above.