Change some events, fix p2 sending gameend twice

- Fixed gameend being sent twice in p2
- Add `ready`, `loader-error`, and `song-select-random` events
- Fixed `session-start` not firing when invited, added event detail
- Fixed `language-change` being fired at startup
- Fixed `version-link` and `about-link` firing twice
- "#song=" will fire `song-select-difficulty`
- Removed `key-events` and `scoresheet-player2`, merged with `scoresheet` and made it more detailed

public/src/js/songselect.js

@@ -313,6 +313,9 @@ class SongSelect{
 		this.redraw()
 		pageEvents.send("song-select")
 		pageEvents.send("song-select-move", this.songs[this.selectedSong])
+		if(songIdIndex !== -1){
+			pageEvents.send("song-select-difficulty", this.songs[this.selectedSong])
+		}
 	}
 	
 	keyDown(event, code){
@@ -615,6 +618,7 @@ class SongSelect{
 				setTimeout(() => {
 					this.moveToSong(moveBy)
 				}, 200)
+				pageEvents.send("song-select-random")
 			}else if(currentSong.action === "tutorial"){
 				this.toTutorial()
 			}else if(currentSong.action === "about"){