Make note optional when sending BTC #125

Please make the input of a note when sending BTC optional. I have seen the other issues and i know it is intention, but please don't force the users to feature they don't want. I think most of the users will not use this field and just enter some random chars (like me) just to be able to send. If you are paying in a shop you want to pay as fast as possible and entering a note slows the process down a lot. Also when almost all notes are random chars they are more confusing then just empty. So please make it optional or create a setting where the user can enable it if he wants to.