Move the join in get_files() to SQL land
Move the join in get_files() to SQL land

Make SQLite3 do the weird join between opened and executed files,
instead of feeding query results through heapq.merge().

JosuaKrause/reprozip,JosuaKrause/reprozip,ViDA-NYU/reprozip,JosuaKrause/reprozip,ViDA-NYU/reprozip,ViDA-NYU/reprozip,JosuaKrause/reprozip,ViDA-NYU/reprozip,ViDA-NYU/reprozip