Token Staking Contract Update

<p dir="auto">TL/DR: Token contract update for hive engine slated for Oct 6th. <p dir="auto">An update to the <code>tokens contract has been <a href="https://github.com/hive-engine/steemsmartcontracts/pull/8" target="_blank" rel="noreferrer noopener" title="This link will take you away from hive.blog" class="external_link">merged into the hive engine repository, and it resolves a discrepancy between how unstaking works when compared to Hive. For tokens that have an unstaking cooldown over more than 1 transaction, the reported amount unstaked will no longer be removed all at once. Instead, it will compute the next batch of tokens to be released, and only remove that amount. <p dir="auto">Note that this should not be a visible impact, because Scotbot does not use the stake balance to do voting or mining (it has its own recording that matches the change that is happening now). But if any other services are using the stake balance, this will be a slight change in how balances are reported. <p dir="auto">The contract updates how the total stake for all holders is counted accordingly, and it also does an initial backfill on deployment, so that all the stake balances will be corrected. <p dir="auto">Why now? This is preparing the contract system for a later update involving bringing mining to the contract level, rather than the current state in Scotbot (this contract is already complete and is under review right now). And further, it will allow a future modification to the mining contract that will incorporate NFTs as well. <p dir="auto">This also sets things up for possibly putting the voting contract itself into Hive Engine. <p dir="auto">We are planning to deploy the new tokens contract on Oct 6th.