update readme and license explanation

README.md

@@ -1,2 +1,11 @@
 # orchard
+
 Fireworks-based workflow management for using and benchmarking ML/CIDER XC functionals.
+
+If you use the vcml\_data module, please cite the paper by Trepte and Voss: https://doi.org/10.1002/jcc.26872
+
+The vcml\_data module is licensed under Creative Commons 4.0, which allows copying and requires
+appropriate credit be given. A copy of the LICENSE is in `EXTERNAL_LICENSES/vcml_data/LICENSE`.
+The files were copied from the original repository without changes, with the exception
+of one line in `eval.py` (line 454).
+

orchard/vcml_data/eval.py

@@ -1,3 +1,8 @@
+# NOTE: Code originally from https://gitlab.com/kaitrepte/vcml_data/
+# See EXTERNAL_LICENSES/vcml_data/LICENSE for the license info
+# that applies to this code and to the data files in this directory,
+# which are all licensed under Creative Commons 4.0.
+
 import os
 import numpy
 import matplotlib.pyplot as plt
@@ -446,6 +451,8 @@ def get_values(self,functional):
             self.label = 'VCML-v'
         idx = get_idx(functional)   # Get the index corresponding to the position of th evalues in file 'all_values.dat'
 
+        # NOTE line changed from original
+        # ffile = open('all_values.dat','r')
         ffile = open(os.path.join(os.path.dirname(__file__), 'all_values.dat'), 'r')
         lines = ffile.readlines()
         ffile.close()