Unhashable type: "list"

Not sure if this library is even maintained. But this is a bug (`definitions.py:186`):
```
type = map.get(eve_type, (eve_type,))
```

because you can have a schema like this:
`"type": ["string", "integer"],`

And so you get this error:
```
TypeError: unhashable type: 'list'
```