Ingame gathering speed tooltip

[elexis]

Since promotion and techs (fish) change the gatherrate, it should be shown in the selection details and panels.

Notice some stone mines / pyramids have other gatherrates (stone.ruins). From the players point of view, it would be nice to show these if these actually occur on the map, but that might be ugly to implement. Another idea might be to add this information to the tooltips, but that seems wrong as the translations would have to be updated everytime someone changes that balancing. Third option would be to continue to ignore it, but it would be nice to reveal this fact to players. (Maybe a loading tooltip?)