Added 20 sets to [DGC] Collection

Previews & DDL:

	[DGC] 2010.03 No.821 Miyuu Ishihara 石原美优
	[DGC] 2010.03 No.822 Chiemi Takayama 高山智恵美
	[DGC] 2010.04 No.823 Mikie Hara 原幹恵
	[DGC] 2010.04 No.824 Aki Hoshino ほしのあき
	[DGC] 2010.04 No.825 Erina Matsui 松井絵里奈
	[DGC] 2010.04 No.826 Hina Kurumi くるみひな
	[DGC] 2010.04 No.827 Megu Fujiura 藤浦めぐ
	[DGC] 2010.04 No.828 Akari Asahina 朝日奈あかり
	[DGC] 2010.04 No.829 Yuri Kashiwagi 柏木友梨
	[DGC] 2010.04 No.830 Sakura Haruno 春野さくら
	[DGC] 2010.04 No.831 Mikoto Sakura 佐倉みこと
	[DGC] 2010.05 No.832 Akina Aoshima 青島あきな
	[DGC] 2010.05 No.833 Akina Aoshima 青島あきな & Natsuko Tatsumi 辰巳奈都子
	[DGC] 2010.05 No.834 Natsuko Tatsumi 辰巳奈都子
	[DGC] 2010.05 No.835 Ai Kawanaka 河中あい
	[DGC] 2010.05 No.836 Rina Rukawa 瑠川リナ
	[DGC] 2010.05 No.837 Yukiko Suo 周防ゆきこ
	[DGC] 2010.05 No.838 Kokomi Sakura 桜ここみ
	[DGC] 2010.05 No.839 Asana Kawai 河井あすな
	[DGC] 2010.05 No.840 Rika Hoshimi 星美りか