Removed global ca::TrackFit instance from ca::TripletConstructor.
Removed access to ca::InputData from ca::TripletConstructor (all needed data is already in ca::WindowData).
Switched from global to window-based hit index in ca::Branch. Allows simplification of many interfaces
(removal of ca::InputData).
Cleaned up ca::TrackFinder.
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.