Custom scripting, #song=, translations

- A song can be linked directly by adding "#song=<id>" to the url, replace `<id>` with the id in the database, after loading it jumps immediately jumps to the difficulty selection
- Added tutorial translations
- Fixed song preview not playing
- Use text fallback for the logo when there are no vectors
- Increased combo cache by 1 pixel
- A custom javascript file can be loaded from config.json by defining "custom_js" value
- Added lots of events to help writing custom js files: `version-link, title-screen, language-change, song-select, song-select-move, song-select-difficulty, song-select-back, about, about-link, tutorial, import-songs, import-songs-default, session, session-start, session-end, debug, load-song, load-song-player2, load-song-unfocused, load-song-cancel, load-song-error, game-start, key-events, p2-game-end, p2-disconnected, p2-abandoned, pause, unpause, pause-restart, pause-song-select, game-lag, scoresheet, scoresheet-player2`
- Event syntax example:
```js
addEventListener("game-start", event => {
	console.log("game-start", event.detail)
})
```

public/src/js/loader.js

@@ -25,6 +25,12 @@ class Loader{
 		
 		var queryString = gameConfig._version.commit_short ? "?" + gameConfig._version.commit_short : ""
 		
+		if(gameConfig.custom_js){
+			var script = document.createElement("script")
+			this.addPromise(pageEvents.load(script))
+			script.src = gameConfig.custom_js + queryString
+			document.head.appendChild(script)
+		}
 		assets.js.forEach(name => {
 			var script = document.createElement("script")
 			this.addPromise(pageEvents.load(script))
@@ -147,8 +153,15 @@ class Loader{
 				}
 			}))
 			
+			var songId
+			var hashLower = location.hash.toLowerCase()
 			p2 = new P2Connection()
-			if(location.hash.length === 6){
+			if(hashLower.startsWith("#song=")){
+				var number = parseInt(location.hash.slice(6))
+				if(number > 0){
+					songId = number
+				}
+			}else if(location.hash.length === 6){
 				p2.hashLock = true
 				this.addPromise(new Promise(resolve => {
 					p2.open()
@@ -182,7 +195,7 @@ class Loader{
 					perf.load = Date.now() - this.startTime
 					this.canvasTest.clean()
 					this.clean()
-					this.callback()
+					this.callback(songId)
 				})
 			}, this.errorMsg.bind(this))