ENH: Better rename/set_names handling for Index
Fixes #4628
- MultiIndex now responds correctly to `rename` (synonym for
  `set_names`)
- `set_names` checks that input is list like.
- Cleaner error message for immutable ops.
- Added in previously missing tests for MultiIndex immutable metadata.
- Altered `is_list_like` to check for binary_types as well.

For now, this is the behavior for Index.rename. It's simple and clear and lets existing code just work instead of dealing with typechecks:

``` python
In [2]: ind = Index(range(10))

In [3]: ind = ind.rename((u'A', u'B'))

In [4]: ind.name
Out[4]: (u'A', u'B')

In [5]: ind.names
Out[5]: FrozenList([(u'A', u'B')])
```
