replaced place holder pop icons

Added new good cola nut as 2nd input for cola plant. I'm planning to give all plants a second input good.
Changed AI strat.

Thanks to the power of a mighty AI, I was able to create some icons to replace the place holders.

turned out, black markets could spawn even for the player.
It seems that the option for auto placing buildings would ignore the possible condition on the building.
also the option to spawn building with trade routes like the trade center seems to ignore the possible setting on the building. (to sad, that would be my prefered option)
So I changed how the systems works. The AI should now try to build black markets by themself and should have desire to export trade goods.
I also added a few black markets that should spawn in random countries at the start of the game.

release 0.2

-replaced some icons
-added et_texticons.txt
-changed german translation

release 0.1