add comments

src/org/oscim/layers/tile/TileDistanceSort.java

@@ -74,6 +74,7 @@ public class TileDistanceSort {
 			int n = start - left;
 
 			if (n < 16) {
+				// shift in loop for less than 16 items
 				int end = left + n;
 				while (end-- > left)
 					a[end + 1] = a[end];

src/org/oscim/layers/tile/vector/MapTileLoader.java

@@ -93,7 +93,7 @@ public class MapTileLoader extends TileLoader implements IRenderCallback, IMapDa
 	// currently processed MapElement
 	private MapElement mElement;
 
-	// current line layer, will be added to outline layers
+	// current line layer (will be used for following outline layers)
 	private LineLayer mCurLineLayer;
 
 	private int mDrawingLayer;