The Linden, a 28-floor downtown Austin condo tower planned in the previously rarely-developed northwestern corner of downtown Austin, is one step closer to becoming this area’s first major residential tower in many years. Along with a recent city permit for the installation of a 418-foot crane implying pending construction, a demolition application filed earlier this week is now in review for clearing the 1980s office structure atop the 0.3-acre site at . . .