slot.value is different from slot[:].wait()

Assuming we have some slot called `slot`:

```
d = {0 : "astring"}
slot.setValue(d)
slot[:].wait() # returns the full dictionary
slot.value  # returns the string "astring"
```

`Slot.value()` assumes that the value was wrapped in a `numpy.ndarray`. Either this should happen automatically in `Slot.setValue()`, or this assumption should be weakened.
