Ordering should be kept when OrderedDict records are passed
When passing a list OrderedDict objects to `pd.DataFrame`, the ordering of the columns is not kept:

``` python
od =  OrderedDict([('Z', 5), ('xx', 8), ('uno', 2), ('etc', 1), ('j', 76), ('e', 7)])
l = [od]*4
pd.DataFrame(l).columns
#Out[23]: Index(['Z', 'e', 'etc', 'j', 'uno', 'xx'], dtype='object')
```
