Added balance to tooltip and send coin option to tray menu

Too features which I thought would be very useful is an easy way to view your balance without opening up the whole application, so I added the balance to the tooltip.

I also felt that adding a send coins option was nice, as there is even less reason to open up the whole bitcoin client just to send some coins.

Please note that I may not have done the translations (that is, used _()) perfectly regarding the tooltips, so please check that first.