Various py3k test failures in tests.io.test_html with US-ASCII preferred encoding
#### Code Sample, a copy-pastable example if possible

```python
>>> import locale
>>> locale.getpreferredencoding()
'US-ASCII'
>>> open('/usr/local/lib/python3.4/site-packages/pandas/tests/io/data/spam.html').read()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.4/encodings/ascii.py", line 26, in decode
    return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 21552: ordinal not in range(128)
>>>
```
#### Problem description

Three tests, `test_string_io`, `test_string`, and `test_file_like`, all open `spam.html` without specifying the encoding, and then attempt to read it. This causes the tests to terminate prematurely with an error.

#### Expected Output

All three tests should pass since the code under test is not responsible for determining the file encoding.

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

<details>
INSTALLED VERSIONS
------------------
commit: None
python: 3.4.6.final.0
python-bits: 64
OS: FreeBSD
OS-release: 10.3-STABLE
machine: amd64
processor: amd64
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.20.1
pytest: 3.1.0
pip: None
setuptools: 32.1.0
Cython: None
numpy: 1.11.2
scipy: 0.19.0
xarray: None
IPython: None
sphinx: None
patsy: None
dateutil: 2.6.0
pytz: 2016.10
blosc: None
bottleneck: 1.0.0
tables: 3.4.2
numexpr: 2.6.2
feather: None
matplotlib: None
openpyxl: 2.4.7
xlrd: 1.0.0
xlwt: None
xlsxwriter: 0.9.6
lxml: 3.6.0
bs4: 4.5.1
html5lib: 0.9999999
sqlalchemy: 1.1.10
pymysql: 0.7.11.None
psycopg2: 2.7.1 (dt dec pq3 ext lo64)
jinja2: 2.9.5
s3fs: None
pandas_gbq: None
pandas_datareader: None
</details>
