While regtesting with [bitcoin-spock](https://github.com/msgilligan/bitcoin-spock) I noticed at some point the transaction creation via `sendtoaddress -> CreateTransaction()` fails, because the created transaction is larger than `MAX_STANDARD_TX_SIZE`.

During the process a lot of raw transactions are created, which have smallish outputs and when then using `sendtoaddress`, it appears to attempt to create a transaction that spends too many of those dust-ish outputs.

The transaction to create does not have many outputs, but it looks like it's caused by the coin selection, which selects too many inputs. Testing was done with a 0.9 branch, but on the first glimpse I believe this issue is as well be present in 0.10. If this is a known issue, and if there is already a guard against this behavior, I'd be happy about a hint.

Sorry in advance, I do not have a test script to reproduce this issue in an isolated manner. A potential fix would probably require to adjust the coin selection, so that it selects a combination of coins, which, in addition to the size of the rest of the transaction, is still smaller than the limit.

backtrack = true;
        } else if (curr_value >= selection_target) {       /
            curr_waste += (curr_value - selection_target); /
            /
            /
            /
            /
            if (curr_waste <= best_waste) {
                best_selection = curr_selection;
                best_waste = curr_waste;
            }
            curr_waste -= (curr_value - selection_target); /
            backtrack = true;
        }
        if (backtrack) { /
            if (curr_selection.empty()) { /
                break;
            }
            /
            for (--utxo_pool_index; utxo_pool_index > curr_selection.back(); --utxo_pool_index) {
                curr_available_value += utxo_pool.at(utxo_pool_index).GetSelectionAmount();
            }
            /
            assert(utxo_pool_index == curr_selection.back());
            OutputGroup& utxo = utxo_pool.at(utxo_pool_index);
            curr_value -= utxo.GetSelectionAmount();
            curr_waste -= utxo.fee - utxo.long_term_fee;
            curr_selection.pop_back();
        } else { /
            OutputGroup& utxo = utxo_pool.at(utxo_pool_index);