doc: Update and improve Developer Notes
doc: Update and improve Developer Notes

peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin,peercoin/peercoin,peercoin/peercoin,peercoin/peercoin,DigitalPandacoin/pandacoin,DigitalPandacoin/pandacoin,peercoin/peercoin,DigitalPandacoin/pandacoin