Core/MMaps: Add rcMedianFilterWalkableArea() to mmaps generation process

Add rcMedianFilterWalkableArea() to mmaps generation process to simplify some ground/water areas

(cherry picked from commit 7ddbc18aafe61434971013ed6126f5666011ab43)

src/tools/mmaps_generator/MapBuilder.cpp

@@ -614,6 +614,12 @@ namespace MMAP
                     continue;
                 }
 
+                if (!rcMedianFilterWalkableArea(m_rcContext, *tile.chf))
+                {
+                    printf("%s Failed filtering area!                  \n", tileString.c_str());
+                    continue;
+                }
+
                 if (!rcBuildDistanceField(m_rcContext, *tile.chf))
                 {
                     printf("%s Failed building distance field!         \n", tileString.c_str());