BUG: pd.unique treats 0 and False as equivalent
```python
In [1]: import pandas as pd

# Simple example
In [2]: pd.unique([0, False])
Out[2]: array([0])

# Testing issue in test_datetime_bool for PR 17077
In [4]: pd.unique([0, False, pd.NaT, 0.0])
Out[4]: array([0, nan], dtype=object)
```
#### Problem description
Currently a testing blocker (`test_datetime_bool`) for PR #17077 

I am guessing False is getting coerced to 0 when determining uniqueness; however, there may be cases when the user wants False to be distinct from 0.

#### Expected Output
```
# Simple example
In [2]: pd.unique([0, False])
Out[2]: array([0, False])

# Testing issue in test_datetime_bool for PR 17077
In [4]: pd.unique([0, False, pd.NaT, 0.0])
Out[4]: array([0, False, nan], dtype=object)
```
#### Output of ``pd.show_versions()``

<details>

INSTALLED VERSIONS
------------------
commit: 86e9dcc164760c5197438968151b2b852647de84
python: 2.7.13.final.0
python-bits: 64
OS: Linux
OS-release: 4.4.0-45-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: None.None

pandas: 0.22.0.dev0+50.g86e9dcc
pytest: 3.2.1
pip: 9.0.1
setuptools: 27.2.0
Cython: 0.26
numpy: 1.13.1
scipy: 0.19.1
pyarrow: None
xarray: None
IPython: 5.3.0
sphinx: 1.5.6
patsy: 0.4.1
dateutil: 2.6.1
pytz: 2017.2
blosc: None
bottleneck: 1.2.1
tables: 3.4.2
numexpr: 2.6.2
feather: None
matplotlib: 2.0.2
openpyxl: 2.4.8
xlrd: 1.0.0
xlwt: 1.2.0
xlsxwriter: 0.9.8
lxml: 3.8.0
bs4: 4.3.2
html5lib: 0.9999999
sqlalchemy: 1.1.13
pymysql: 0.7.9.None
psycopg2: 2.7.1 (dt dec pq3 ext lo64)
jinja2: 2.9.6
s3fs: None
fastparquet: None
pandas_gbq: None
pandas_datareader: None
</details>
