Added example for address from private key

examples/address_from_private_key/address_from_private_key.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"log"
+
+	"github.com/bitcoinschema/go-bitcoin"
+)
+
+func main() {
+
+	// Start with a private key
+	privateKey, err := bitcoin.CreatePrivateKeyString()
+	if err != nil {
+		log.Fatalf("error occurred: %s", err.Error())
+	}
+
+	// Get an address
+	var address string
+	if address, err = bitcoin.AddressFromPrivateKey(privateKey); err != nil {
+		log.Fatalf("error occurred: %s", err.Error())
+	}
+
+	// Success!
+	log.Printf("found addres: %s from private key: %s", address, privateKey)
+}