Wallet fee & utxo fixups

- `utxo.receive` renamed to `utxo.from`
- `getUnspentOutputs` now includes the `pending` field
- do not overestimate fees when `network` has `dustSoftThreshold`

`estimateFeePadChangeOutput ` was adding an output with amount zero, which works for bitcoin as it does not care about the amount when estimating tx fee. It causes a consistent overestimation when it comes to networks with a soft dust threshold used for applying additional fees when the output amount is below that threshold. 

Now with the proposed modification there's a chance that we could be underestimating -- when the change amount happens to fall below the soft dust threshold. But for lite & doge the slight underestimation is acceptable?