Explain boost source in popups

**Issue by [vttale](https://github.com/vttale)**
_Saturday Nov 19, 2016 at 03:57 GMT_
_Originally opened as https://github.com/CQUI-Org/cqui/issues/116_

----

The popup that lists that we've gotten a boost for something it doesn't really say why clearly, though the prose often hints at why. It'd be nice if where it said BOOSTED it gave what the requirement for the boost was.

Ideally, it would depend on how the boost was REALLY earned, but I don't know if you have access to that. That is, while it is usually from the requirement listed in the tree they can come from any of a goody hut, a great person, or a city-state bonus. It'd be nice if it was explicit how the boost happened.

Locate the Lua UI popup that displays BOOSTED and inspect what boost information the game exposes there. The work is done when the popup clearly identifies why the boost was earned, including sources such as the listed requirement, a goody hut, a great person, or a city-state bonus when distinguishable.

Written by the indexing model from the issue text.