Update to sending tips feature: burning 1% as fee

Hi guys, an update to the sending tips feature provided by @tipU. From today 1% of the tip will be burned by sending it to @null.

free blockchain wallpaper :)

So if you send 0.1 Hive tip, the recipient will receive 0.99 Hive and 0.01 will be sent to @null.

The reason is that soon (few days) tips will be implemented on peakd.com and they will have this burning mechanic to avoid abusing. I wanted those two ways of sending tips (using @tipU and peakd) to be consistent so they can be presented the same way :)