Use the current selected terrain Palette from the selected Map.

Use the current selected terrain Palette from the defined Tileset in the Map. 
- The Tileset is defined in "map.yaml" at "Tileset:"
- The color palette is defined in the "<Tileset>.yaml" at "Palette:"
Merge pull request #6485 from LipkeGu/patch-3

Use the current selected terrain Palette from the selected Map.