Mobile voice and chat startup iSkoot has made a small acquisition: it has bought social IM aggregator client Social.im, according to Techcrunch. iSkoot was the first company to work with Skype to bring the service to mobiles, and has raised about $14 million in two rounds, with investors such as Khosla Ventures and Charles River Ventures. Social.im has developed a client to enable chat with all your Facebook friends, and integrates other clients such as MSN, Yahoo (NSDQ: YHOO) IM and AOL…but with Facebook launching its own IM client, its popularity perhaps never took off. Now the hope is mobile integration…