Updated groundwar planet surface rendering: (#1170)

- Surface and radar minimap are drawn into a buffered image that is then drawn to the screen. The images are redrawn only in case of an event that changes the visual appearance of the planet surface.
  - Radar minimap is transformed to a rectangle and added an orange rectangle as a frame to resemble the og ig minimap.

src/hu/openig/gfx/ColonyGFX.java

@@ -57,7 +57,7 @@ public class ColonyGFX {
     /** The tile crossed. */
     @Img(name = "colony/tile_1x1_selected_crossed")
     public BufferedImage tileCrossed;
-    /** The tile crossed. */
+    /** The tile paved. */
     @Img(name = "colony/tile_1x1_pavement")
     public BufferedImage tilePavement;
     /** Upgrade panel. */

src/hu/openig/model/PlanetSurface.java

@@ -1115,6 +1115,14 @@ public boolean hasRoad(int x, int y) {
         public boolean hasCrossRoad(int x, int y) {
             return (surfaceArray[getArrayIndexForLocation(x, y)] & CROSSROAD) != 0;
         }
+        /**
+         * Check if a location has building on it.
+         * @param loc the location
+         * @return true if surface tile has building on it
+         */
+        public boolean hasBuilding(Location loc) {
+            return (surfaceArray[getArrayIndexForLocation(loc.x, loc.y)] & BUILDING) != 0;
+        }
         /**
          * Check if a cell is buildable.
          * @param x the X coordinate