Beatmap downloader improvements and fixes.

Updates:
- Added some buttons to downloads menu: clear inactive downloads, import beatmaps, reset search, and show/hide unranked maps.
- Small changes to OsuParser, OszUnpacker, and OsuGroupList (mostly adding return values) to allow parsing only newly unpacked beatmaps.
- Added alpha fade hover effect to MenuButton, as an alternative to expanding (used for 3-part menu buttons).
- Added text rendering fields to MenuButton (also for the 3-part menu buttons).
- Added sound effects to downloads menu.

Fixes:
- Check downloads for illegal filename characters, and remove them if necessary.
- The number of results and downloads shown now supports all resolutions.
- Confirmation dialog no longer appears when restarting the application (since downloads are static).
- Do not set a focus node immediately if the theme song will be played.
- Always play the theme song if no songs are loaded (even if disabled in settings).

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

src/itdelatrisu/opsu/downloads/Download.java

@@ -19,6 +19,7 @@
 package itdelatrisu.opsu.downloads;
 
 import itdelatrisu.opsu.ErrorHandler;
+import itdelatrisu.opsu.Utils;
 
 import java.io.File;
 import java.io.FileOutputStream;
@@ -155,8 +156,9 @@ public class Download {
 						rbc.close();
 						fos.close();
 						if (rename != null) {
+							String cleanedName = Utils.cleanFileName(rename, '-');
 							Path source = new File(localPath).toPath();
-							Files.move(source, source.resolveSibling(rename), StandardCopyOption.REPLACE_EXISTING);
+							Files.move(source, source.resolveSibling(cleanedName), StandardCopyOption.REPLACE_EXISTING);
 						}
 					}
 				} catch (Exception e) {