Fix infinity arrow adding after quest completion

[sven-n]

Added two fixes for the problem, that the inifinity arrow skill didn't get add to the character after quest completion:

• Generally, stat attributes which are defined in the character class, but not in the character, are added automatically as soon as the player enters the game.
• Fixed initialization code. Since the inifinty arrow quest reward was the last database update, i just fixed that and increased its number.

Another minor fix was defining the maximum master level to the initialization code of season 6.