Improve performance of periodical chunk progress saving task

src/main/kotlin/net/trivernis/chunkmaster/lib/generation/GenerationManager.kt

@@ -307,8 +307,8 @@ class GenerationManager(private val chunkmaster: Chunkmaster, private val server
                     percentage,
                     eta,
                     chunkSpeed!!,
-                    genTask.lastChunk.x,
-                    genTask.lastChunk.z))
+                    genTask.lastChunkCoords.x,
+                    genTask.lastChunkCoords.z))
                 saveProgressToDatabase(genTask.lastChunkCoords, task.id)
                 genTask.updateLastChunkMarker()
             } catch (error: Exception) {

src/main/kotlin/net/trivernis/chunkmaster/lib/generation/GenerationTask.kt

@@ -116,8 +116,8 @@ abstract class GenerationTask(
             markerSet?.creUpdateAreMarker(
                 markerLastId,
                 markerLastName,
-                this.lastChunk.getBlock(0, 0, 0).location,
-                this.lastChunk.getBlock(15, 0, 15).location,
+                this.lastChunkCoords.getCenterLocation(world).chunk.getBlock(0, 0, 0).location,
+                this.lastChunkCoords.getCenterLocation(world).chunk.getBlock(15, 0, 15).location,
                 markerLastStyle
             )
         }