Added "favorites" and "last played" beatmap groups, and more sorts.

- New sorts: by date added, and most played.
- Sorts are moved to a dropdown menu.
- Tabs are now groupings (all songs, last played, favorites).
- Add/remove "favorite" beatmaps in the right-click menu.
- Beatmap database is now updateable like score database (no longer drops/recreates on every update).
- Various bug fixes.

Signed-off-by: Jeffrey Han <itdelatrisu@gmail.com>

src/itdelatrisu/opsu/beatmap/BeatmapParser.java

@@ -120,6 +120,7 @@ public class BeatmapParser {
 
 		// parse directories
 		BeatmapSetNode lastNode = null;
+		long timestamp = System.currentTimeMillis();
 		for (File dir : dirs) {
 			currentDirectoryIndex++;
 			if (!dir.isDirectory())
@@ -163,6 +164,7 @@ public class BeatmapParser {
 
 				// add to parsed beatmap list
 				if (beatmap != null) {
+					beatmap.dateAdded = timestamp;
 					beatmaps.add(beatmap);
 					parsedBeatmaps.add(beatmap);
 				}