added commentary for new struct

include/libhqr.h

@@ -90,13 +90,16 @@ typedef struct libhqr_tiledesc_s{
 } libhqr_tiledesc_t;
 
 
+/**
+ * @brief Minimal structure to stock the information for each tile
+ */
 typedef struct libhqr_tileinfo_s{
-    int type;
-    int currpiv;
-    int nextpiv;
-    int prevpiv;
-    int first_nextpiv;
-    int first_prevpiv;
+    int type;          /** The type of the tile                             */
+    int currpiv;       /** Number of the time annihilating the current tile */
+    int nextpiv;       /** The next tile killed by the tile                 */
+    int prevpiv;       /** The previous tile killed by the tile             */
+    int first_nextpiv; /** The first next tile killed                       */
+    int first_prevpiv; /** The first previous tile killed                   */
 } libhqr_tileinfo_t;
 
 struct libhqr_tree_s;