ENH: dtype('bool') ndarray or Series coerced to dtype('int') in qcut GH20303

- [x] closes #20303 
- [x] tests added / passed
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Currently, passing a `dtype('bool')` `ndarray` or `Series` as argument to `qcut` raises a `TypeError`.  As was suggested in #20303, now `_coerce_to_type` also coerces `bool` types to `int`. 
Hello @tomasfarias! Thanks for updating the PR.





Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on March 24, 2018 at 03:05 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20400?src=pr&el=h1) Report
> Merging [#20400](https://codecov.io/gh/pandas-dev/pandas/pull/20400?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/cdfce2b0ad99f7faad57cc5247cf33aab5725bed?src=pr&el=desc) will **decrease** coverage by `0.02%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/20400/graphs/tree.svg?height=150&width=650&token=eZ4WkYLtcO&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/20400?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #20400      +/-   ##
==========================================
- Coverage   91.82%    91.8%   -0.03%     
==========================================
  Files         152      152              
  Lines       49248    49209      -39     
==========================================
- Hits        45222    45175      -47     
- Misses       4026     4034       +8
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.18% <100%> (-0.03%)` | :arrow_down: |
| #single | `41.85% <0%> (-0.05%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/20400?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/core/reshape/tile.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS90aWxlLnB5) | `93.52% <100%> (+0.15%)` | :arrow_up: |
| [pandas/io/s3.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3MzLnB5) | `72.72% <0%> (-13.64%)` | :arrow_down: |
| [pandas/core/arrays/base.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL2Jhc2UucHk=) | `80.64% <0%> (-3.51%)` | :arrow_down: |
| [pandas/io/common.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2NvbW1vbi5weQ==) | `68.77% <0%> (-1.27%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `83.95% <0%> (-0.58%)` | :arrow_down: |
| [pandas/core/groupby.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZ3JvdXBieS5weQ==) | `92.14% <0%> (-0.42%)` | :arrow_down: |
| [pandas/plotting/\_core.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb3JlLnB5) | `82.27% <0%> (-0.24%)` | :arrow_down: |
| [pandas/io/parsers.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL3BhcnNlcnMucHk=) | `95.32% <0%> (-0.13%)` | :arrow_down: |
| [pandas/io/formats/csvs.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvY3N2cy5weQ==) | `98.05% <0%> (-0.09%)` | :arrow_down: |
| [pandas/core/algorithms.py](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYWxnb3JpdGhtcy5weQ==) | `94.29% <0%> (-0.07%)` | :arrow_down: |
| ... and [18 more](https://codecov.io/gh/pandas-dev/pandas/pull/20400/diff?src=pr&el=tree-more) | |

------

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> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/20400?src=pr&el=footer). Last update [cdfce2b...ff0e328](https://codecov.io/gh/pandas-dev/pandas/pull/20400?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 can you rebase closing as stale. pls ping if can update