Singer-songwriter Taio Cruz, who famously performed during the London Olympics closing ceremony in 2012, is entering the social networking cosmos with a new app intended to mash up functions from existing apps such as Facebook, Foursquare, Instagram and WhatsApp. KeWe -- a portmanteau of "Key" and "We" (as in "KeWe is the Key to the We") -- is Cruz's first foray into the app market. Cruz's firm, T