[bug] "GAME_STORAGE_DIR" variable is unused

[moonburnt]

Tried to implement os-specific directories, but it all came down to one issue - while cookies, manifest, !downloading and !orphaned are easy to move, GAME_STORAGE_DIR variable (which looks like something thats supposed to represent directory where game files will be moved at the end), despite being specified at the very beginning of script - in reality is never used anywhere.

Suggestion: well, just make it usefull (say, at the end of cmd_download() function)