Icon button

[cloverich]

Required for #215

• Implement an internal IconButton
• Incorporate tooltip with inner text (or text as property).

But dont go overboard. I expect a tooltip when hovering preferences in the application. But then, theres not that much functionality in the app, and once you click it, you know what it is. And someone who never clicks it, is likely not going to be a serious user of the application anyways.