Bramble fix - game examples included

[Thrutchy]

This seems like a reasonable solution for bramble. I think the root of the problem is that each thorn is a spawn point - of thorns. Now that thorns can attack, this becomes a huge advantage. If this fix is too crippling, here are a few ideas:

- allow a thorn to attack, grow, and recede in the same turn
- attack by 2 - probably too much
- healing a healed bramble heals its closest non-healed thorn
- no wit for killing thorn

Another option is to remove the ability for the thorn to attack and leave recede. But the multi-spawn (defense) seems like it still could be dangerous.