make: time+cpu-prof test-fads-app
cmd/tasks: update for new fwk.Register
hepmcreader: update for new fwk.Register
propagator: update for new fwk.Register
datamodel: make Candidates Clone()-able
hepmcreader: make input Reader a bufio.Reader
propagator: implement particle propagation
momentum_smearing: first import
efficiency: first import
test-fads-app: add more tasks