This evening, Austin's Historic Landmark Commission will hear the details of a proposed 12-story tower addition to the historic Bartholomew-Robinson Building at the southeast corner of West 15th and Lavaca Streets downtown. The project would seemingly integrate elements of the existing single-story building, which dates back to the 1880s, into the new structure's ground floor, while raising a tower for "micro-hotel" brand Motto by Hilton above the 0.14-acre tract at 1415 Lavaca . . .