What's Changed
* get_response add_0=True correct index by martinvonk in https://github.com/pastas/pastas/pull/325
* Kraijenhoff van de Leur Response by martinvonk in https://github.com/pastas/pastas/pull/326
* docformatter, autopep8 and sort imports by dbrakenhoff in https://github.com/pastas/pastas/pull/328
* Histogram in plots.series() by martinvonk in https://github.com/pastas/pastas/pull/330
* Add ChangeModel to dev by raoulcollenteur in https://github.com/pastas/pastas/pull/332
* Add Spline response function by rubencalje in https://github.com/pastas/pastas/pull/333
* pastas.plots.series() changes by martinvonk in https://github.com/pastas/pastas/pull/334
* allow kwargs for rsq by martinvonk in https://github.com/pastas/pastas/pull/341
* Kraijenhoff van de Leur / Bruggeman 133.15 Response by martinvonk in https://github.com/pastas/pastas/pull/335
* Add `get_equidistant_timeseries()` method by dbrakenhoff in https://github.com/pastas/pastas/pull/338
* Improve Flexmodel and add a snow model by raoulcollenteur in https://github.com/pastas/pastas/pull/343
* Fix 353, precision of floats in JSON files by dbrakenhoff in https://github.com/pastas/pastas/pull/354
* Save and read options of FlexModel to/from pas-file by rubencalje in https://github.com/pastas/pastas/pull/359
* Update master to v0.19.0 by raoulcollenteur in https://github.com/pastas/pastas/pull/362
**Full Changelog**: https://github.com/pastas/pastas/compare/v0.18.0...v0.19.0