Implement Bountysource widget

Since recent time Bountysource began offering small widgets for websites: http://blog.bountysource.com/post/87257081709/bountysource-badges. I suggest to place a widget in a good-visible part of ReactOS website (in the future – instead of "Join the revolution"-banner). Code of widget your can find in the lower part of left margin of https://www.bountysource.com/trackers/896453-reactos-core page.