Support 'True' and 'False' strings as boolean settings values

'1' and '0' are supported.
I think we can support "True" and "False".
I would still test the output of `json.loads()` to `True` or `False` explicitly
```python
>>> bool(json.loads("{}"))
False
>>> bool(json.loads("[]"))
False
>>> bool(json.loads("[1]"))
True
>>> bool(json.loads("[0]"))
True
>>> bool(json.loads('{"a": 32}'))
True
>>> json.loads('True'.lower())
True
>>> json.loads('false'.lower())
False
>>> json.loads('{"a": 32}'.lower()) == True
False
>>> 
```