Duke3D: While per-map art is active, selecting "End Game" and then reloading a save will not reload the art properly

To reproduce this, extract the files from this archive into the eduke32 folder, and start the first episode: permap_test.zip

Then, save the game in the level, and select the End Game option, then reload the save (might need to be done twice in a row). This occurs because previousboardfilename is not updated when selecting the "End Game" menu option.

In MR !192 (merged) I address this issue by removing the hack that was introduced to prevent loading the same mapart multiple times when loading saves. The problem with that hack is that the previousboardfilename needs to be updated whenever the mapart is cleared, which is prone to error. The hack is no longer necessary anyways, because caching is now dynamic, and can no longer crash the game.