Merge pull request #5 from samuelhward/patch-1

Add visualisation packages: VTK and Vista

Author: TomNicholas

README.md

@@ -346,10 +346,11 @@ Basically magic, compatible with pytest, and the algorithms used in the implemen
 * [holoviews](http://holoviews.org/) - Stop plotting your data - annotate your data and let it visualize itself.
 * [ipyvolume](https://ipyvolume.readthedocs.io/en/latest/index.html#built-on-ipywidgets) - 3d plotting for Python in the Jupyter notebook.
 * [vispy](http://vispy.org/index.html) - Interactive scientific visualisation in python.
+* [vtk](https://pypi.org/project/vtk/) - Low-level VTK interface
+* [vista](https://docs.pyvista.org/) - Streamlined interface to VTK - mainly a wrapper for VTK package
 * [yt](http://yt-project.org/) - Very powerful software suite for analysing and visualising volumetric data.
 Written by astrophysicists, but since applied to many other domains.
 
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 ## Workflow
 
 *Don't just write and run python scripts. Tools to make your workflow faster, clearer, and easier to come back to later.*