python make.py html

Traceback (most recent call last):
  File "doc/make.py", line 23, in <module>
    import pandas
ModuleNotFoundError: No module named 'pandas'

I believe a slight bug was introduced by c8859b5 in including import pandas at the top of the script. Unless the user has pandas installed as a package I don't think this module would know where to find it without modifying the path or being more explicit on import

@jorisvandenbossche