Avoid errors when options.cfg has no data

In that case res==False which was not accounted for, resulting in
AttributeError: 'bool' object has no attribute 'items'.

Closes #193.

pysollib/options.py

@@ -648,7 +648,7 @@ class Options:
         vdt = validate.Validator()
         res = config.validate(vdt)
         # from pprint import pprint; pprint(res)
-        if res is not True:
+        if isinstance(res, dict):
             for section, data in res.items():
                 if data is True:
                     continue