In this commit the alpha detail map placements have also been remastered manually. Now there's no more rock detail map placements where there's supposed to be water, etc.
This commit replaces the current planet textures with upscaled originals. Therefore, the issues caused after adding the updated planet detailmaps are now fixed. However, there are still some minor issues and other inconsistencies with the new textures. Those will be fixed in future commits.
