Before, all TBFs would start with Amp = 1, leading to a norm > 1
Changed this by adjusting Amp initialisation,
but is that the right way to go?

for checking if Bundle with 2 initial TBFs is correctly created
but nothing else

In OverlapModule for checking bundle set up

Changes to SelectionModule:
- alternative selection if singlet and triplet states
- selection only happens for singlet only or triplet only
  blocks of coupled trajectories (not for S/T mixed blocks)
Other changes:
- Starting with more than one initial Gaussian
  (NumInitBasis > 1)
- Displacing Gaussians using swarm in SamplingModule
  (this only works for the SOC model, as it assumes 1D)

- Amplitudes are normalised to separated block and renormalised to
  total bundle after selection
- Issue of no normalisation if selection happens in first separated
  block fixed
- Index of trajectories to kill only changed if selection happened
  (added IsSelection to perform_stochastic_selection for this)
- Commented out a bunch of print statements

Relevant change:
- loop for translating indices which trajectory to kill now
  starts at 1 instead of 2

fixed the reordering of blocktrajid into blocks that correspond
to the stochastic selection modes (i.e. all Singlet-only block
trajids in one column, all Triplet-only in one column, before
this did not work if a block was spread over more than two
individual blocks)

Also, activated a set of useful prints for debugging

- realised that the TrajIDs can remain unchanged when copying from
  B1 into the spin-separated bundles
- realised that, with the TrajIDs remaining unchanged, all that needs
  to be copied back to B1 after a selection are the amplitudes

WiP

- restructured main loop of SelectionModule into one

- got rid of unused variables
- commented out print statements
- added a fix for Singlet and Triplet selection happening
  at the same time step
  (making sure that dead trajs of both selections are marked for death)