json encoding for python 2
#### Code Sample, a copy-pastable example if possible
```python 
# not working
pd.read_json(path, encoding='cp1251')

# that works
import json 
with open(path, 'r') as f:
    js = json.load(f, encoding='cp1251')
pd.DataFrame(js)
```
#### Problem description
It is not mentioned explicitly in docstring that `encoding` option used in py3 only.

Currently `pd.read_json` mostly ignores `encoding=` option in python2.
Function `pd.common._get_handle` warns about using encoding with compression, but silently continues without actually using `encoding` otherwise.

It looks like subtasks are split in unfavourable way to pass encoding up to `json.loads` call.
#### Expected Output
One might expect pandas use encoding, to get life easier (as pandas usually do ;) ).
Or at least properly warn that option is ignored.

#### Output of ``pd.show_versions()``
<details>
INSTALLED VERSIONS
------------------
commit: None
python: 2.7.12.final.0
python-bits: 64
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 58 Stepping 9, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: None.None

pandas: 0.19.2
nose: 1.3.7
pip: 9.0.1
setuptools: 28.8.0.post20161110
Cython: 0.24.1
numpy: 1.12.0
scipy: 0.18.1
statsmodels: 0.6.1
xarray: None
IPython: 5.1.0
sphinx: 1.4.6
patsy: 0.4.1
dateutil: 2.5.3
pytz: 2016.6.1
blosc: None
bottleneck: 1.0.0
tables: 3.2.2
numexpr: 2.6.2
matplotlib: 2.0.0
openpyxl: 2.3.2
xlrd: 1.0.0
xlwt: 1.1.2
xlsxwriter: 0.9.2
lxml: 3.6.4
bs4: 4.3.2
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.13
pymysql: 0.7.6.None
psycopg2: None
jinja2: 2.8
boto: 2.40.0
pandas_datareader: None
</details>
