implement tslibs/src to make tslibs self-contained
Hello @jbrockmendel! Thanks for updating the PR.



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

##### Comment last updated on August 01, 2018 at 18:11 Hours UTC looks good. a build is failing, maybe rebase and push again. # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22152?src=pr&el=h1) Report
> Merging [#22152](https://codecov.io/gh/pandas-dev/pandas/pull/22152?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/9c118668256d2e36d2d310d46e604392a92bbee7?src=pr&el=desc) will **not change** coverage.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/22152/graphs/tree.svg?width=650&height=150&src=pr&token=eZ4WkYLtcO)](https://codecov.io/gh/pandas-dev/pandas/pull/22152?src=pr&el=tree)

```diff
@@           Coverage Diff           @@
##           master   #22152   +/-   ##
=======================================
  Coverage   92.06%   92.06%           
=======================================
  Files         170      170           
  Lines       50707    50707           
=======================================
  Hits        46682    46682           
  Misses       4025     4025
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.47% <ø> (ø)` | :arrow_up: |
| #single | `42.3% <ø> (ø)` | :arrow_up: |


------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22152?src=pr&el=continue).
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> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/22152?src=pr&el=footer). Last update [9c11866...54ac680](https://codecov.io/gh/pandas-dev/pandas/pull/22152?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 thanks, progress bit-by-bit