Created a modules folder for the graph_tools so they can be used by all samples added the references to the function

Author: lmalenfant

.gitignore

@@ -1,3 +1,4 @@
 **/.ipynb_checkpoints/
 forward-solvers/__pycache__/
 libraries/
+modules/__pycache__/

forward-solvers/fluence-of-rho-and-z-two-layer.py

@@ -11,6 +11,9 @@
 import clr
 # Import the Operating System so we can access the files for the VTS library
 import os
+import sys
+module_path = '../modules'
+sys.path.append(module_path)
 file = '../libraries/Vts.dll'
 clr.AddReference(os.path.abspath(file))
 import numpy as np

forward-solvers/phd-of-rho-and-z-compute-fluence.py

@@ -9,6 +9,9 @@
 import clr
 # Import the Operating System so we can access the files for the VTS library
 import os
+import sys
+module_path = '../modules'
+sys.path.append(module_path)
 file = '../libraries/Vts.dll'
 clr.AddReference(os.path.abspath(file))
 import numpy as np

forward-solvers/phd-of-rho-and-z-two-layer.py

@@ -9,6 +9,9 @@
 import clr
 # Import the Operating System so we can access the files for the VTS library
 import os
+import sys
+module_path = '../modules'
+sys.path.append(module_path)
 file = '../libraries/Vts.dll'
 clr.AddReference(os.path.abspath(file))
 import numpy as np