IndexError using converters in read_html
`read_html` returns a list of DF.  Giving a `converters` parameter (see #13461) applies the converters on each DF. Keys of the converters, when being integers, can not be greater than the number of columns minus 1 of the parsed DF (otherwise it raises an IndexError exception in io.parser.PythonParser._convert_data ).
But most of the time, DFs returned by  `read_html` are of different sizes. Thus converters are unusable on all columns of index greater `min([len(df.column) for df in pd.read_html(url)])`


#### Example

```python
import pandas

def converter_one(c):
    return 1

d = {0 : converter_one, 1 : converter_one}
d2 = {0 : converter_one, 1 : converter_one, 2 : converter_one}
url = 'https://web.archive.org/web/20160419075502/http://clients.rte-france.com/lang/an/visiteurs/vie/prod/prevision_production.jsp'
pandas.read_html(url, converters = d2)
```

#### Expected Output
As in
```python
pandas.read_html(url, converters = d)
```

This issue may also prevent to change `read_html`as proposed in #14608 

#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Darwin
OS-release: 15.6.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: None
LANG: fr_FR.UTF-8
LOCALE: fr_FR.UTF-8

pandas: 0.19.1
nose: 1.3.7
pip: 8.1.2
setuptools: 23.0.0
Cython: 0.25.1
numpy: 1.11.2
scipy: 0.17.1
statsmodels: 0.6.1
xarray: None
IPython: 4.2.0
sphinx: 1.4.1
patsy: 0.4.1
dateutil: 2.5.3
pytz: 2016.7
blosc: None
bottleneck: 1.1.0
tables: 3.2.2
numexpr: 2.6.0
matplotlib: 1.5.1
openpyxl: 2.3.2
xlrd: 1.0.0
xlwt: 1.1.2
xlsxwriter: 0.9.2
lxml: 3.6.0
bs4: 4.4.1
html5lib: 1.0b8
httplib2: None
apiclient: None
sqlalchemy: 1.0.13
pymysql: None
psycopg2: None
jinja2: 2.8
boto: 2.40.0
pandas_datareader: None
</details>
