Reduce block reward or/and increase mining difficulty

[d47081]

Maybe the subject for another fork, but current rewards allows to DoS the blockchain using PC mining.

Related commits

• https://github.com/kevacoin-project/kevacoin/commit/f80d9fed49088f3bb1bbb9d7223d438714d10100
• https://github.com/kevacoin-project/kevacoin/commit/d814fc3128f6f1ea27d6d4a978b624857bc9e72a
• https://github.com/kevacoin-project/kevacoin/commit/41b708cb1bfccf077b13882493c0941ccaf5d916

Related issues

• 26