Suggestion: improve management of recieving and sending addresses

[pereira4]

Right now it's too simple and a bit messy. I would like to be able to create groups and have them nicely ordered, instead of a raw list that can get ordered by alphanumerical order at best without any possible ways to separate them.
Also, add a key shortcut to pop up the receiving/sending addresses window (f4 for receiving window f5 for sending, would be really useful, it's annoying to click everytime).