Apple has acquired indoor GPS company WifiSLAM for around $20 million. WifiSLAM is a two-year-old startup that has developed ways for mobile apps to detect the location of a phone in a building with Wi-Fi. A brief description of the company notes applications including step-by-step indoor navigation, product-level retail customer management, and proximity-based social networking. The addition of the technology will theoretically help Apple competeā¦