[WIP] Jedi API for Python REPLs

I just noticed that I can create fake scopes from "raw" Python objects.  This is just a quick first version of it.  Currently it just treats objects with `__module__` attribute.  I need to treat other cases such as instance and module.  I thought I'd post it first before I am going to wrong direction.

Here is a working example:
```py
    >>> from itertools import chain
    >>> script = Interpreter('cha', [locals()])
    >>> script.complete()
    [<Completion: chain>]
```