to_stata: Fixed width strings in Stata .dta files are limited to 244 (or fewer)
#### Code Sample, a copy-pastable example if possible

```python
import pandas
frame = pandas.DataFrame({'A':['h'*250,'hi','hola']})
frame.to_excel("text.xlsx", index=False)
frame.to_stata("test.dta")

```
#### Problem description

Raises the following error: 
> ValueError:
> Fixed width strings in Stata .dta files are limited to 244 (or fewer)
> characters.  Column 'A' does not satisfy this restriction.

However this restriction seems to not exists in STATA, as the Excel file can be imported correctly
Open STATA, import the Excel file

```STATA
import excel "C:\data\tesi\software\text.xlsx", sheet("Sheet1") firstrow clear

```
Now we can get the type of data in column 'A', and as you can see, it's str250. So STATA can store string longer than 244 characters

```STATA
. describe A

```
A               str250  %250s                 A

#### Expected Output
File gets exported with the correct format and without problems

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

<details>
INSTALLED VERSIONS
------------------
commit: None
python: 3.5.2.final.0
python-bits: 64
OS: Windows
OS-release: 10
machine: AMD64
processor: Intel64 Family 6 Model 94 Stepping 3, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.19.2
nose: 1.3.7
pip: 9.0.1
setuptools: 23.0.0
Cython: 0.24
numpy: 1.11.2
scipy: 0.18.1
statsmodels: None
xarray: None
IPython: 4.2.0
sphinx: 1.5.5
patsy: None
dateutil: 2.5.3
pytz: 2016.6.1
blosc: None
bottleneck: None
tables: 3.2.3.1
numexpr: 2.6.1
matplotlib: 1.5.3
openpyxl: 2.4.7
xlrd: 1.0.0
xlwt: None
xlsxwriter: None
lxml: 3.7.3
bs4: 4.5.3
html5lib: 0.999999999
httplib2: None
apiclient: None
sqlalchemy: None
pymysql: None
psycopg2: None
jinja2: 2.8
boto: None
pandas_datareader: 0.2.1
</details>
