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/p2.js

@@ -128,7 +128,6 @@ class P2Connection{
 				for(var i in response.value){
 					this.results[i] = response.value[i].toString()
 				}
-				pageEvents.send("scoresheet-player2", this.results)
 				break
 			case "note":
 				this.notes.push(response.value)