CLN: Enigma DataReader

[femtotrader]

Following #245

Some code cleanup is required
see https://travis-ci.org/pydata/pandas-datareader/jobs/166965935

Pinging @trevorprater @gregorykremler @m1teyssier

$ flake8 --ignore E501 pandas_datareader
pandas_datareader/base.py:4:1: F401 'datetime as dt' imported but unused
pandas_datareader/base.py:7:1: F401 'requests_file.FileAdapter' imported but unused
pandas_datareader/base.py:9:1: F401 'pandas.to_datetime' imported but unused
pandas_datareader/base.py:11:1: F401 'pandas.core.common.is_number' imported but unused
pandas_datareader/enigma.py:2:1: F401 'json' imported but unused
pandas_datareader/enigma.py:4:1: F401 'sys' imported but unused
pandas_datareader/enigma.py:8:1: F401 'pandas.DataFrame' imported but unused
pandas_datareader/enigma.py:45:20: E711 comparison to None should be 'if cond is None:'
pandas_datareader/enigma.py:47:30: E711 comparison to None should be 'if cond is None:'
pandas_datareader/enigma.py:59:1: W293 blank line contains whitespace
pandas_datareader/enigma.py:60:5: E303 too many blank lines (2)
pandas_datareader/enigma.py:69:1: W293 blank line contains whitespace
pandas_datareader/enigma.py:70:5: E303 too many blank lines (2)
pandas_datareader/enigma.py:74:1: W293 blank line contains whitespace
pandas_datareader/enigma.py:75:5: E303 too many blank lines (2)
pandas_datareader/enigma.py:81:1: W293 blank line contains whitespace
pandas_datareader/enigma.py:82:5: E303 too many blank lines (2)
pandas_datareader/enigma.py:85:1: W293 blank line contains whitespace
pandas_datareader/enigma.py:86:5: E303 too many blank lines (2)
pandas_datareader/tests/test_enigma.py:3:1: F401 'requests' imported but unused
pandas_datareader/tests/test_enigma.py:8:1: F401 'pandas.util.testing.assert_series_equal' imported but unused
pandas_datareader/tests/test_enigma.py:8:1: F401 'pandas.util.testing.assert_frame_equal' imported but unused

Could you open an other PR to fix this ?

[sinhrks]

we should merge NO prs which failed on travis.

[femtotrader]

we really need to fix #226