``set_state()`` method quietly accepts transposed array

```
>>> model = Model()
>>> x = model.integer((2, 5))
>>> with model.lock():
... model.states.resize(2)
... x.set_state(0, [[1, 2], [1, 3], [4, 1], [3, 2], [5, 5]])
... x.set_state(1, [[1, 2, 3, 4, 5], [5, 4, 3, 2, 1]])
... print(x.state(1))
... print(x.state(0))
[[1. 2. 3. 4. 5.]
[5. 4. 3. 2. 1.]]
[[1. 2. 1. 3. 4.]
[1. 3. 2. 5. 5.]]
```

It's a nice "feature" to use but it will probably trip someone up.