Moved files to folders, modified some imports.

vkoga_2L.py → vkoga_2l/vkoga_2L.py

 #!/usr/bin/env python3
 
-from kernels import Matern
+from vkoga_2l.kernels import Matern
 import numpy as np
 from sklearn.base import BaseEstimator
 from sklearn.utils.validation import check_X_y, check_array, check_is_fitted
 from scipy.spatial import distance_matrix
 import torch
-from utilities import OptimizedKernel
+from vkoga_2l.utilities import OptimizedKernel
 
 
 # VKOGA implementation