Former Highland Capital Partners venture capitalist Walt Doyle is now the CEO of a new startup, but it's still in stealth mode. Doyle was the founder and CEO of Where Inc., which was acquired in 2011 by PayPal Media Network for a reported $135 million, forming the basis for PayPal's Boston division. Doyle, in a chat at BostInno's State of Innovation event on Tuesday, said he is keeping mum about the new startup, for now. After the Where acquisition, Doyle was general manager of PayPal until 2013,...