Pyvista

This version marks the beginning of this software being released as PyVista:

bash
pip install -U pyvista

Bug fixes
- Objects would sometimes not be collected due to way the scalar dictionary was initialized.
- Windows plots now close without having to press ``q``.
- ``__repr__`` method for most objects now displays correctly.

Features
- Added opacity example.
- Added movie example.
- Now using ``vtkLightingKit`` for lighting rather than a single headlamp.

Changes
- ``show_bounds`` is now ``show_grid`` when using ``vtki.plot``

- Fix Delaunay spelling mistake per 118
- `vtki.PolyData.delauney_2d` -> `vtki.PolyData.delaunay_2d`
- Add `delaunay_2d` filter to `vtki.UnstructuredGrid`
- Update size limit for `repr` to automatically compute the volume of mesh
- Update scalar bar arguments and add [usage example](http://docs.vtki.org/en/latest/examples/quick/plot-scalar-bars.html)
- Enable DICOM reader [per this thread](https://discourse.vtk.org/t/how-to-improve-vtkdicomimagereader-output/430/2)
- Add dark plotting theme: `vtki.set_plot_theme('dark')`
- Add global topography download examples
- Add DICOM knee download example
- `pycharm` `PIL` hotfix

Bug Fixes:

- Fixed issue with saving screenshots after exiting the window (see 109)
- General updates and bug fixes for the readers/writers
- Update `__repr__` methods on all objects
- Fix `lighting` keyword argument issues

Additions

- Downloadable sample datasets: `examples.download_*`(see 112)
- `PolyData` `*.vtp` reader/writer
- Abstract class protections (see 113)
- Support plotting multi component arrays (see 114)
- Camera resetters for viewing common planes (see 115)
- Camera disable/enable functions for plotter (see 115)
- More choices for camera interaction styles
- `vtki.BasePlotter.enable_*_style`
- Ability to contour when slicing
- See docs for [`vtki.DataSetFilters.slice`](http://docs.vtki.org/en/latest/tools/filters.html#vtki.DataSetFilters.slice)
- New Isocontour IPython tool (see [docs](http://docs.vtki.org/en/latest/tools/ipy_tools.html#isocontour) and 117)
- Enable Rectilinear grids to be instantiated as 2D

Major new changes

- A major overhaul to plotting code:
- Most notably: new subplotting code (see 107 and [Multi-Window Plot](http://docs.vtki.org/en/latest/examples/quick/multi-window.html))
- Keyword arguments updates (see 106)
- New universal reading code added to parse file extensions for the appropriate VTK reader see 100

Notable Changes

- Volume calculation code. See 103, [Volumetric Analysis](http://docs.vtki.org/en/latest/examples/quick/compute-volume.html), and new filters
- Many new filters (see [Filters](http://docs.vtki.org/en/latest/tools/filters.html#dataset-filters)):
- `split_bodies` (see 104)
- `warp_by_scalar`
- `triangulate`
- `cell_data_to_point_data`
- `delaunay_3d`
- `PolyData.smooth` (see [Volume Smoothing](http://docs.vtki.org/en/latest/examples/quick/volume-smoothing.html))
- Scalar bar updates (see 85 and 106)
- Added ability to orbit a rendering scene: `BasePlotter.orbit_on_path`
- New input text (float) fields next to the sliders on the Qt scale axes dialog. See 96 and 101
- Includes better testing of Qt plotting code
- Improvements to code quality from issues raised by [Codacy](https://app.codacy.com/project/banesullivan/vtki/dashboard)
- Legacy reader is now more robust - reads all data in the file
- Refactor of `load_texture` to `read_texture`
- Plot textures by default if available and no preferences given
- More geometric objects (see [Geometric Objects](http://docs.vtki.org/en/latest/tools/geometric.html)):
- `vtki.Line`
- `vtki.Cube`
`vtki.Cone`
- `vtki.Box`
- `vtki.Polygon`
- `vtki.Disc`
- `vtki.MultiBlock` updates
- Get block by key name
- New geo-focused example dataset `examples.load_channels` (see 108)
- Windows key bug fixed (see 92)
- Major documentation updates with auto summaries