bug: read_csv incorrect output with skipfooter and skip_blank_lines=True
read_csv does not return the data table expected if there's only one line in the CSV file and skipfooter is used and the line directly after the table is blank and skip_blank_lines=True.

```
>>> import pandas as pd
>>> import StringIO
>>> test_csv = StringIO.StringIO('a,b,c\n1,2,3\n\nend\n')                                                                                                                                                                                      
>>> pd.read_csv(test_csv, skip_footer=2, engine='python')
Empty DataFrame
Columns: [a, b, c]
Index: []
```

But if the more than one line is in the data table or the line after the data table is not blank or skip_blank_lines is set to False, everything is ok:

```
>>> test_csv = StringIO.StringIO('a,b,c\n1,2,3\n4,5,6\n\nend\n')
>>> pd.read_csv(test_csv, skip_footer=2, engine='python')
   a  b  c
0  1  2  3
1  4  5  6
>>> test_csv = StringIO.StringIO('a,b,c\n1,2,3\nend\n\n')
>>> pd.read_csv(test_csv, skip_footer=2, engine='python')
   a  b  c
0  1  2  3
>>> test_csv = StringIO.StringIO('a,b,c\n1,2,3\n\nend\n')
>>> pd.read_csv(test_csv, skip_footer=2, engine='python', skip_blank_lines=False)
   a  b  c
0  1  2  3
```

This occurs in every version from 0.15.0 onwards (ie since skip_blank_lines was introduced).
