list index out of range

The code

`"params" : {"A" : []}`

causes

`Error: 'list index out of range'!`

That's wrong. There is no list index out of range. It should be possible, to initialize an empty list.

No such problems if the empty list is a list element:

`"params" : {"A" : ["B", []]}`

is resolved properly:

`DotDict({'params': DotDict({'A': ['B', []]})})`

