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/titlescreen.js

@@ -15,7 +15,7 @@ class Titlescreen{
 			this.logo = new Logo()
 		}
 		this.lang = this.getLang()
-		this.setLang(allStrings[this.lang])
+		this.setLang(allStrings[this.lang], true)
 		
 		if(songId){
 			this.goNext()
@@ -106,7 +106,7 @@ class Titlescreen{
 		}
 		return "ja"
 	}
-	setLang(lang){
+	setLang(lang, initial){
 		strings = lang
 		
 		loader.screen.style.fontFamily = strings.font
@@ -129,7 +129,9 @@ class Titlescreen{
 		this.disclaimerCopyright.setAttribute("alt", strings.titleCopyright)
 		
 		this.logo.updateSubtitle()
-		pageEvents.send("language-change", lang.id)
+		if(!initial){
+			pageEvents.send("language-change", lang.id)
+		}
 	}
 	addLangs(){
 		for(var i in allStrings){