BUG: Fix the rename function for Series and DataFrame, #3165
### Bug 1: After `rename`, the `name` of the `index` is missing:

```
In [1]: import pandas as pd

In [2]: data = [1, 2]

In [3]: index = pd.Index(['a', 'b'], name='name')

In [4]: df = pd.DataFrame(data, index=index)

In [5]: df 
Out[5]: 
      0
name   
a     1
b     2

In [6]: df.rename({'a': 'c'})
Out[6]: 
   0
c  1
b  2
```

Both `Series` and `DataFrame` has the same problems. The reason is that we didn't set the `name` of the `index` while reconstructing the `DataFrame/Series` by `rename` .
### Bug 2: `rename` cannot work for the `MultiIndex` case, the `index` becomes tuples, the `names` of the index are gone

```
In [1]: import pandas as pd

In [2]: data = [1, 2]

In [3]: index = pd.MultiIndex.from_tuples([('a', 'b'), ('c', 'd')], names=['name1', 'name2'])

In [4]: df = pd.DataFrame(data, index=index)

In [5]: df
Out[5]: 
             0
name1 name2   
a     b      1
c     d      2

In [6]: df.rename({'a': 'e'}) 
Out[6]: 
        0
(a, b)  1
(c, d)  2
```

The missing name issue is same as Bug1. The original `rename` function convert the dict to the mapper function and map each tuple but not each index, and doesn't reconstruct it as `MultiIndex`, so it becomes a `Index` with some tuples.
### Fix

I've fixed the above two bugs, the `rename` will also pass the `name` of the `index` too, the `rename` mapper will go through each index for the `MultiIndex` case now.
I also added some test cases in `test_series.py` and `test_frame.py`

This looks great!
 @waitingkuo you beat me too it! looks good
 Hope this might help : )
 Please add an entry to RELEASE.rst
