BUG: Escape `<` and `>` in info _repr_html_

Closes https://github.com/pydata/pandas/issues/7105

Before: http://nbviewer.ipython.org/gist/TomAugspurger/4c83a646ffb93d5ee978
After: http://nbviewer.ipython.org/gist/TomAugspurger/81bf15086864ca090bb6

After conosle:

```
In [28]: df
 Out[5]: 
<class 'pandas.core.frame.DataFrame'>
Int64Index: 2 entries, 0 to 1
Data columns (total 2 columns):
0    2 non-null float64
1    2 non-null float64
dtypes: float64(2)
```

FYI, I don't know HTML, but I think this is mostly right.