Recommendation/Feature request: Simple address book

[TBO-git]

This is not a bug but a feature request:

To make it more convenient for the users simple address book (address labeling) functionality would good, so that the users can distinguish between his/her smartcash addresses as well as smartcash addresses of known individuals (e.g. friends) better. The user shall be able to define a label for each address in his wallet and also define labels to addresses not in his wallet.

The labels given shall appear next to where the address is shown (e.g. on the address navigation bar on the left, the chat recipient list on the smart chat tab, the smart reward tab)