bitcoinjs-lib fixed types, added re-exports

[dl3br]

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[dt-bot]

types/bitcoinjs-lib/index.d.ts

to authors (@mhegazy @rbuckton). Could you review this PR?
👍 or 👎?

Checklist

• pass the Travis CI test?

[dcousens]

No optional string, Buffer only

[dcousens]

fromBase58Check returns {hash, version}, see https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/src/address.js#L16

[dcousens]

| number? nope