An exercise group can keep using the old Lansdale Power Plant site for its military-style fitness workouts. Borough Council approved use of the site, at Third Street and Richardson Avenue, on Tuesday and Thursday evenings.  Councilman Rich DiGregorio says homes are nearby, so approval is on a trial basis, and council might have to reconsider its approval if the neighbors complain about noise.  Doctor Drill Instructor is Doctor Aaron Oberst, a Lansdale Chiropractor and former U.S. Marine, and he is paying a fee for use of the property.