Type cast in spaces families

[XuehaiPan]

1. spaces.Dict

in __init__:

• convert tuple to OrderedDict as well (same as list)
• raise AssertionError when the user does not pass a dict or list / tuple of keyvalue pairs.

2. spaces.Tuple:

in __init__:

• convert input spaces to tuple:

in contains:

• convert the input sample to tuple:

Fixes #2140.
Fixes #2479.

3. spaces.MultiBinary:

in __init__:

• convert input shapes to tuple of ints.
• raise AssertionError when any entry of the input shapes is not positive.

4. spaces.MultiDiscrete:

in __init__:

• make a copy of the input nvec

  >>> import numpy as np
  >>> a = np.array([1, 2, 3], np.int64)
  >>> np.asarray(a) is a
  True
  
  >>> np.asarray(a)[0] = 4
  >>> a
  array([4, 2, 3])

• raise AssertionError when any entry of the input shapes is not positive (convert to ints first).

in contains:

• convert tuple to np.ndarray as well (same as list)

5. spaces.Discrete:

in __init__:

• convert the input shape int.
• raise AssertionError when the input shape is not positive (convert to ints first).

[XuehaiPan]

Closed due to changing branch name.