* ethcore: fix pow difficulty validation * ethcore: validate difficulty is not zero * ethcore: add issue link to regression test * ethcore: fix tests * ethcore: move difficulty_to_boundary to ethash crate * ethcore: reuse difficulty_to_boundary and boundary_to_difficulty * ethcore: fix grumbles in difficulty_to_boundary_aux  | 
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| .. | ||
| pool | ||
| external.rs | ||
| gas_price_calibrator.rs | ||
| gas_pricer.rs | ||
| lib.rs | ||
| work_notify.rs | ||