MultiIndex smart repr fmt doesn't work well for complex examples
``` python
In [42]: labels = [('foo', 1),
    ...:  ('foo', 2),
    ...:  ('bar', 3),
    ...:  ('bar', 4)]
    ...: pd.MultiIndex.from_tuples(labels)
Out[42]: 
MultiIndex
[foo  1,      2, bar  3,      4]
```

hiding the repeated `foo` and `bar` is nice for small multindices, but
for more levels and more complex structures, it can becomes
harder to read. The blanks also keep their width, and the  result
isn't very attractive when presented as a single line:

``` python
labels = [('foo', '2012-07-26T00:00:00', 'b5c2700'),
    ...:  ('foo', '2012-08-06T00:00:00', '900b2ca'),
    ...:  ('foo', '2012-08-15T00:00:00', '07f1ce0'),
    ...:  ('foo', '2012-09-25T00:00:00', '5c93e83'),
    ...:  ('foo', '2012-09-25T00:00:00', '9345bba')]
    ...: pd.MultiIndex.from_tuples(labels)

MultiIndex
[append_frame_single_homogenous  2012-07-26  b5c2700,                     2012-08-06  00b2ca,                                 2012-08-15  07f1ce0,                                 2012-09-25  5c93e83,                                             9345bba]

```
