SoundBuffer: Set song volume

- Requires a new column in the database after preview: `volume` REAL
- The value is a volume multiplier, if the value is set to null or 1 there will be no change
- The volume can be set in debugger
- Imported TJA files are now read from disk every time the song is played, freeing some memory and making it easier to create charts
- Correctly parse TJA files with alphabet notes, added "A" and "B" notes, which appear as DON (Big) and KA (Big) respectively

public/src/js/strings.js

@@ -1,7 +1,7 @@
 function StringsJa(){
 	this.id = "ja"
 	this.name = "日本語"
-	this.regex = /^ja$/
+	this.regex = /^ja$|^ja-/
 	this.font = "TnT, Meiryo, sans-serif"
 	
 	this.taikoWeb = "たいこウェブ"