In ca::TrackFinder, replaced separate vector instances which store
upper and lower bounds of windows by single vectors that store
these bounds together as a pair.
Cleaned up ca::TripletConstructor.
Removed global ca::TrackFit instance from ca::TripletConstructor.
Removed access to ca::InputData from ca::TripletConstructor (all needed data is already in ca::WindowData).
Cleaned up and refactored ca::TrackFinderWindow.
Removed global triplets array in ca::TrackFinderWindow.