Design idea: menu of buttons on main gameplay screen

[bgstack15]

A short list of buttons somewhere on the main UI could solve a number of the feature requests, such as #59, #27, #124.

Maybe a config option that accepts arbitrary text, image url, link url, and tooltip text for a button?
If you make a main <div> for such a menu, it will be easier to add them one at a time as more features are implemented. If it's collapsible/pop up, then you don't lose space on the main UI for all those things.