gitignore
Direct SLP function (not debugged yet)

FIXME: directSLP don't build the eigenvectors from the base
coordinates

- directSLP: resolves the problem

- _directSLP_FPMbase: returns the FPM base of size N

- _directSLP_inner1: given the differentiation matrix and the
  transformed potential, returns the transformed eigenvectors and
  eigenvalues

- _directSLP_inner2: returns the differntiation matrix