Fix estimation of tx inputs #142

At the moment, the estimateTxSize function expects a simple numInputs arg becuase it assumes all inputs are of type p2wpkh | p2sh(p2wpkh), therefore the estimation for txs that include other types of inputs may not be accurate.

This can be fixed by expecting a list of input script types + 2 lists of auxiliary redeeem script sizes and witness sizes instead of the numInputs one. The auxiliary arrays can be easily reconstructed from a pset in wallet.buildTx, or properly crafted from wallet info in wallet.sendTx

Take a look here for a reference implementation.