Reverted back to instakill artillery rules

[nymanjens]

The old artillery rules are in fact not overpowered. I think we drew conclusions too quickly.

Example: In our test game with these rules, we used to find that 1 artillery vs 1 infantry was OP, but 2 infantry (= same cost) vs 1 infantry has a very high rate of winning anyway.

[317070]

I agree, but I would still be on the lookout for resolving the issue of the 'unfair battle', where you cannot defend yourself.