Generalized improve and added dU functions.
Started to implement the second order improvement process.
Psi is not needed in the improvement outer cycle.
Differentiations of the functions.
Ignore python3 subdirectory.
Removed redundant printing.
Try to establish right axes.
Vector functions now return correct columns and matrices.
Correct variable's psition to be a column instead to be a row.
Removed debug prints.
Bad merge.