Add notifications: Inspiration/Eurekas, Border/Pop growth

**Issue by [0SirLoin](https://github.com/0SirLoin)**
_Friday Nov 25, 2016 at 12:07 GMT_
_Originally opened as https://github.com/CQUI-Org/cqui/issues/143_

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Especially in the late game and with the added popups for having reached inspiration and eureka limits one often misses a lot of this information. Would it be possible to have an option to convert these popups to these permanent infos on the right screen where you can choose when to read them (like having a dow, unit attacked, unit killed etc.)
Also on that matter another suggestion: Like in the community mod pack for Civ5 having such notifications for border growth and population growth would be very helpful because when playing with a lot of cities you often miss these events.

The issue mentions the right-side notification area and popup events but names no files, tests, or entry points. Start by locating the existing notification and popup implementations, then determine how inspiration, eurekas, border growth, and population growth are represented. Done means these events can be surfaced as readable notifications without being easily missed.

Written by the indexing model from the issue text.