BLD/TST: cross compat for pa/fp failing on osx & windows
xref #18662
closes #18714 
this is not great because xfailing entire test. should figure out what actually is failing and only xfail that part. I think fastparquet is using deps which cause an upgrade of numpy here.

```
package plan for installation in environment /Users/travis/miniconda3/envs/pandas:
The following NEW packages will be INSTALLED:
    arrow-cpp:      0.7.1-py35_2               conda-forge
    fastparquet:    0.1.3-py35_0               conda-forge
    feather-format: 0.3.1-py35_1               conda-forge
    llvmlite:       0.21.0-py35h3a66efe_0                 
    numba:          0.36.1-np113py35hd65e1c9_0            
    parquet-cpp:    1.3.0.post-2               conda-forge
    pyarrow:        0.7.1-py35_1               conda-forge
    thrift:         0.10.0-py35_0              conda-forge
The following packages will be UPDATED:
    numpy:          1.10.4-py35_nomkl_2                    [nomkl] --> 1.13.3-py35_nomklh6554414_0 [nomkl]
```

So easiest is to simply use a later version of numpy on this build. I will update. I think this will fail until fastparquet does a release with https://github.com/dask/fastparquet/pull/264 yeah, going to move to 0.22.0 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18715?src=pr&el=h1) Report
> Merging [#18715](https://codecov.io/gh/pandas-dev/pandas/pull/18715?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/b5f1e716d89487423bb12d6cc4e6da2b39184531?src=pr&el=desc) will **decrease** coverage by `0.07%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/18715/graphs/tree.svg?width=650&src=pr&token=eZ4WkYLtcO&height=150)](https://codecov.io/gh/pandas-dev/pandas/pull/18715?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #18715      +/-   ##
==========================================
- Coverage   91.64%   91.57%   -0.08%     
==========================================
  Files         154      153       -1     
  Lines       51430    51307     -123     
==========================================
- Hits        47131    46982     -149     
- Misses       4299     4325      +26
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `89.43% <ø> (-0.06%)` | :arrow_down: |
| #single | `40.71% <ø> (-0.24%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/18715?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/gbq.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2dicS5weQ==) | `25% <0%> (-58.34%)` | :arrow_down: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `64.78% <0%> (-1.74%)` | :arrow_down: |
| [pandas/util/\_test\_decorators.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvX3Rlc3RfZGVjb3JhdG9ycy5weQ==) | `93.33% <0%> (-1.22%)` | :arrow_down: |
| [pandas/core/reshape/melt.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9tZWx0LnB5) | `96.22% <0%> (-1.03%)` | :arrow_down: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `82.01% <0%> (-0.9%)` | :arrow_down: |
| [pandas/core/indexes/category.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9jYXRlZ29yeS5weQ==) | `97.2% <0%> (-0.31%)` | :arrow_down: |
| [pandas/core/categorical.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvY2F0ZWdvcmljYWwucHk=) | `95.64% <0%> (-0.15%)` | :arrow_down: |
| [pandas/io/formats/format.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvZm9ybWF0LnB5) | `96.03% <0%> (-0.15%)` | :arrow_down: |
| [pandas/core/dtypes/dtypes.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvZHR5cGVzL2R0eXBlcy5weQ==) | `95.14% <0%> (-0.14%)` | :arrow_down: |
| [pandas/core/indexes/numeric.py](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9udW1lcmljLnB5) | `97.26% <0%> (-0.11%)` | :arrow_down: |
| ... and [16 more](https://codecov.io/gh/pandas-dev/pandas/pull/18715/diff?src=pr&el=tree-more) | |

------

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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/18715?src=pr&el=footer). Last update [b5f1e71...741ff7f](https://codecov.io/gh/pandas-dev/pandas/pull/18715?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 I blew this away accid, so closing for now.