Replaced 'input_directory' variable in user dictionary with 'inputfile' from which the directory can easily be derived, e.g. os.path.dirname()

docs/source/python_scripting.rst

@@ -19,8 +19,8 @@ You can access the following built-in constants from your Python code:
 You can access the following built-in variables from your Python code:
 
 * ``current_model_run`` is the current run number of the model that is been executed.
+* ``inputfile`` is the path and name of the input file.
 * ``number_model_runs`` is the total number of runs specified when the model was initially executed, i.e. from ``python -m gprMax my_input_file -n number_of_model_runs``
-* ``input_directory`` is the path to the directory where your input file is located.
 
 
 Functions for input commands