* Ethereum Classic Monetary Policy
Create a new parameter `ecip1017EraRounds`. When the block number
passes one era rounds, the reward is reduced by 20%.
See https://github.com/ethereumproject/ECIPs/blob/master/ECIPs/ECIP-1017.md
* Update rewards for uncle miners for ECIP1017
In the monetary policy, the rewards are changed from "up to 7/8 of the
reward" to "1/32 of the reward".
* Fix an off-by-one error in ECIP1017 era calculation
According to
https://github.com/ethereumproject/ECIPs/blob/master/ECIPs/ECIP-1017.md,
when in block number 5,000,000, it should still be in Era 1 (which in
our code `era == 0`). So we need to check whether the `rem` equals to
zero and act accordingly when calculating the era.
* `ecip1017_era_rounds` missing from EthashParams when run in build bot
* strip out ecip1017_eras_block_reward function and add unit test
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