List indices do not work

[iliapolo]

Accessing specific elements in an array/list does not work.

For example, given the following configuration file:

{
  "services": [
          {"a": "b"}, 
          {"a": "c"}
  ]
}

Running this command: dictfile configure config get --key services:1 results in an error:

Error: list indices must be integers, not unicode

While the expected output is {"a": "c"}

Note that we also need positional offset accessors. That is, the following command should also work:

dictfile configure config put --key services:0:a --value d