Added 20 sets to [DGC] Collection

Previews & DDL:

	[DGC] 2008.03 No.561 Yukina Momoyama 桃山ゆきな
	[DGC] 2008.03 No.562 Momo Kasuga 春日桃
	[DGC] 2008.04 No.563 Yuuri Morishita 森下悠里
	[DGC] 2008.04 No.564 Akiko Seo 瀬尾秋子
	[DGC] 2008.04 No.565 Kanako Koda 神田佳菜子
	[DGC] 2008.04 No.566 Mizuki みずき
	[DGC] 2008.04 No.567 Chiemi Mori もりちえみ
	[DGC] 2008.04 No.568 Sora Aoi 蒼井そら
	[DGC] 2008.04 No.569 Maki Hoshino ほしのまき
	[DGC] 2008.04 No.570 Rui Kiriyama 桐山瑠衣
	[DGC] 2008.04 No.571 Miho Kato 加藤美穂
	[DGC] 2008.04 No.572 Naoko Tanaka 田中直乃
	[DGC] 2008.04 No.573 Tomomi Nakamura 仲村ともみ
	[DGC] 2008.04 No.574 Ryo Kanesaki 金咲稜
	[DGC] 2008.05 No.575 Rina Akiyama 秋山莉奈
	[DGC] 2008.05 No.576 Yurina Sato 佐藤ゆりな
	[DGC] 2008.05 No.577 Emi Itoh 伊藤えみ
	[DGC] 2008.05 No.578 Anna Sonoda 薗田杏奈
	[DGC] 2008.05 No.579 Noriko Kijima 木嶋のりこ
	[DGC] 2008.05 No.580 Sasa Handa 範田紗々