CI: rebalance the travis ci jobs
move some from the 3.6 build to 3.7 as the 3.6 is 15 min longer. mark the multi-thread tests as slow.
Hello @jreback! Thanks for updating the PR.

 - There are no PEP8 issues in the file [`pandas/tests/computation/test_eval.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/computation/test_eval.py) !

 - There are no PEP8 issues in the file [`pandas/tests/frame/test_to_csv.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/frame/test_to_csv.py) !

 - There are no PEP8 issues in the file [`pandas/tests/io/parser/multithread.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/io/parser/multithread.py) !

 - There are no PEP8 issues in the file [`pandas/tests/io/sas/test_sas7bdat.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/io/sas/test_sas7bdat.py) !

 - There are no PEP8 issues in the file [`pandas/tests/io/sas/test_xport.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/io/sas/test_xport.py) !

 - There are no PEP8 issues in the file [`pandas/tests/test_resample.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/test_resample.py) !

 - There are no PEP8 issues in the file [`pandas/tests/test_sorting.py`](https://github.com/jreback/pandas/blob/dd8ffd7cbdc1e830f871b43b3f20b30759fde773/pandas/tests/test_sorting.py) !



##### Comment last updated on November 06, 2018 at 02:29 Hours UTC is there a way to skip doc tests if something is not installed? e.g. https://travis-ci.org/pandas-dev/pandas/jobs/446665579

I want to run the doc-tests now on both jobs but skip when the deps are not there I'm not aware of a way to skip doctests based on imports. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23358?src=pr&el=h1) Report
> :exclamation: No coverage uploaded for pull request base (`master@0f99f61`). [Click here to learn what that means](https://docs.codecov.io/docs/error-reference#section-missing-base-commit).
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/23358/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/23358?src=pr&el=tree)

```diff
@@            Coverage Diff            @@
##             master   #23358   +/-   ##
=========================================
  Coverage          ?   91.76%           
=========================================
  Files             ?      161           
  Lines             ?    51169           
  Branches          ?        0           
=========================================
  Hits              ?    46954           
  Misses            ?     4215           
  Partials          ?        0
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.14% <ø> (?)` | |
| #single | `42.28% <ø> (?)` | |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23358?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/23358?src=pr&el=footer). Last update [0f99f61...ba7ace7](https://codecov.io/gh/pandas-dev/pandas/pull/23358?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 yeah i will rebase this later its ok as is now