bittrex canceled status close ccxt#4974

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itbit added ETH markets fix ccxt#4970

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Fix links Bit-Z

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1.18.455

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mercado use safeFloat / safeInteger in parseOHLCV

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livecoin fetchMyTrades() true

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formatting edits in CONTRIBUTING

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kucoin withdraw fix ccxt#4957

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minor linting issue

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fixes ccxt#4954 (kucoin zero priced market orders)

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