Feature request - Add abandon() function to allow funds to be returned

[DouglasHorn]

When an account sends TLOS to works.decide those funds are assigned to the account's funds in the accounts table. This prevents accounts from returning unused funds to Telos Works. An abandon() function is needed that would work exactly like the 'withdraw()' function but without transferring tokens.

An account that holds a balance in the accounts table should be able to abandon those funds with the result that the amount of funds abandoned will be subtracted from the account's entry on the accounts table without sending funds to the account.

Suggested code:

works.hpp insert at line 95

    //abandon funds from account balance
    ACTION abandon(name account_name, asset quantity);

works.cpp Insert at line 682

ACTION works::abandon(name account_name, asset quantity) {

    //authenticate
    require_auth(account_name);

    //validate
    check(quantity.symbol == TLOS_SYM, "can only abandon TLOS");
    check(quantity.amount > 0, "can only abandon a positive amount");

    //subtract balance from account
    sub_balance(account_name, quantity);

}

Update human-language contracts