Payment documentation (#49)

* added factory method FromPublicKeys for creating multiscript payment

* payment documentation

payment/doc.go

@@ -0,0 +1,9 @@
+/*
+Package payment is an abstract for working with all kind of addresses in Liquid network.
+
+It can be used for the creation of p2pkh, p2ms, p2sh, non-native SegWit and native SegWit addresses.
+
+It also provides support for confidential payments.
+
+*/
+package payment

payment/examples_test.go

@@ -0,0 +1,34 @@
+package payment_test
+
+import (
+	"encoding/hex"
+	"fmt"
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/vulpemventures/go-elements/network"
+	"github.com/vulpemventures/go-elements/payment"
+)
+
+const (
+	privateKeyHex = "1cc080a4cd371eafcad489a29664af6a7276b362fe783443ce036552482b971d"
+)
+
+var privateKeyBytes, _ = hex.DecodeString(privateKeyHex)
+
+//This examples shows how standard P2PKH address can be created
+func ExampleFromPublicKey() {
+	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes)
+	pay := payment.FromPublicKey(publicKey, &network.Regtest)
+	fmt.Printf("P2PKH address %v\n:", pay.PubKeyHash())
+}
+
+//This examples shows how nested payment can be done in order to create non native SegWit(P2SH-P2WPKH) address
+func ExampleFromPayment() {
+	_, publicKey := btcec.PrivKeyFromBytes(btcec.S256(), privateKeyBytes)
+	p2wpkh := payment.FromPublicKey(publicKey, &network.Regtest)
+	pay, err := payment.FromPayment(p2wpkh)
+	p2sh, err := pay.ScriptHash()
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Printf("Non native SegWit address %v\n:", p2sh)
+}