Checksum ZPQS after second startup. Removed the menu tab backgrounds. More bugfixes.
# Version 0.52c - 3/30/2021
## Interface Changes:
* Removed background from the menu tabs.
## Bug Fixes:
* Fixed South German Confederation not having a primary culture.
* Fixed Romania and Serbia not getting annexed by Austria-Hungary if the Allies lose WW1 and they surrendered previously and then Bulgaria surrendered after them.
* Cleaned up history files.
## General gameplay changes:
* Assigned some leaders and moved some units around in the WW1 OOBs.