Microsoft’s impending purchase of Mojang, the Swedish developer with 100 million players of its open world Minecraft game, is more aimed at pulling users onto the software company’s obscure mobile platform than its better known PC system or Xbox game console. The software company’s Windows Phone system has only 2.5 percent of the world’s smartphone market, and its Surface tablet barely more, according to tech research firm IDC. Enter Minecraft, which is the top paid app both on Apple Inc’s (AAPL.O) iOS and Google Inc’s (GOOGL.O) Android systems.