BUG: columns misaligned in repr when having >10 columns with integer index
On master, with integer index, with more than 10 columns, the numbers of one char are misaligned:

```
In [37]: df = pd.DataFrame(np.random.randn(10,20))

In [38]: pd.options.display.max_columns = 4

In [39]: df
Out[39]:
         0         1     ...           18        19
0 -0.112066 -0.315377    ...     1.579197 -0.718384
1 -1.007079  0.234835    ...    -0.485022 -0.317984
2 -0.718872  1.094609    ...    -2.083531  0.559202
3 -0.165058 -0.127335    ...     0.296100  1.071882
4  0.874132  0.880632    ...    -1.648739  0.903484
5 -0.443316  0.673899    ...     0.823925  0.365219
6  0.215746  1.092637    ...     0.645429 -1.164019
7  1.853194 -1.682354    ...     1.071287 -0.366133
8 -0.568050 -1.205619    ...    -1.644478 -2.206907
9  2.136091 -0.253217    ...     1.148933  1.390127

[10 rows x 20 columns]

In [40]: df = pd.DataFrame(np.random.randn(10,10))

In [41]: df
Out[41]:
          0         1    ...            8         9
0  0.337429 -0.627859    ...     0.174635  1.378869
1 -1.679982  1.498135    ...     0.554562  1.804903
2  0.682877 -0.539606    ...    -0.065115  0.871922
3  0.517217 -0.850968    ...     0.998076 -1.141827
4  0.131862  1.702232    ...    -1.048214 -1.424597
5  0.926904 -0.120110    ...     0.852535  1.052194
6 -0.474197 -0.984774    ...     1.206264 -0.710416
7  0.532609 -0.797821    ...    -1.082022 -0.137153
8 -0.075104 -0.524546    ...     0.177842 -0.030325
9  1.568465  1.206357    ...     0.410863  1.575516

[10 rows x 10 columns]
```
