Replaced all 'artist' with 'game'

Tables affected:
artist_comments -> game_comments
artists_alias -> games_alias
artists_group -> games_group
artists_last_read_comments -> games_last_read_comments
artists_similar -> games_similar
artists_similar_scores -> games_similar_scores
artists_similar_votes -> games_similar_votes
artists_similar_votes -> games_tags
bookmarks_artists -> bookmarks_games
collages_artists -> collages_games
request_artists -> requests_games
torrents_artists -> torrents_games
users_artists_comments subscriptions -> users_games_comments_subscriptions
wiki_artists -> wiki_games

Fields affected:
ArtistID -> GameID
ArtistName -> GameName
ArtistList -> GameList
Artists -> Games