Fixed minor bugs in PM and encoding

Thanks to @Nicci

Rebalanced Techs

-Stock Exchange now provides 5% MAPI, down from vanilla's 10%.

-Zeppelin no longer provides market access, instead it provides a reduction for military goods. This makes ensure it is still one of the better techs in game.

-Pave roads now provides 5% MAPI.

Rebalanced MAPI and transport generation

-Increased MAPI for freight trains to accommodate the changes in tech

-now freight provides a little bit of transport. This is to avoid edge cases where high-level railway runs better with low-level PM.

-rebalanced productivity. This mod was balanced so railway is about as productive as the average consumer goods factory, but in the old version this did not take into account of throughput bonus. Now railway generates slightly more transport in total.

- Added German Translation (by Ragnarus)
- updated the thumbnail