With just about everyone using a smartphone or tablet these days, there’s almost no excuse to not be in almost constant contact with just about anyone you know. That’s where an ever-changing breed of group messaging apps come into play. Here are three of the best around. Blend combines functionality with flash and simplicity. The app allows users to set up one or more groups of friends, family, co-workers or anyone else. Blend users can take part in video chats, send pictures, or have private chats with individual members of their group or groups. The app is free for iOS and Android users. Tango works on smartphones and tablets, and specializes…