Glueviz

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- Fixed bug that caused session files saved after removing subsets
to no longer be loadable. [253]

- Fixed bug that caused record icon to appear multiple times when
successively creating 3D viewers. [252]

- Fixed bug with volume rendering on Windows with Python 2.7, due to
Numpy .shape returning long integers. [245]

- Fixed bug that caused the flipping of size and cmap limits in the
3D viewers to not work properly. [251]

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- Fixed bugs with 3D selections following refactoring. [243]

- Fixed the case where vmin == vmax for size or color. [243]

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- When multiple datasets are visible in a 3D view, selections now apply to
all of them (except for point and point and drag selections, for which the
selection applies to the currently selected layer). [208]

- The selection tools have been refactored to use the new toolbar/tool
infrastructure in glue. [208]

- Update all layers in 3D viewers if numerical values change in any datasaet. [236]

- Refactored the viewers to simplify the code and make development easier. [238]

- Improve the default level selection for the isosurface viewer. [238]

----------------

- Fixed a bug that caused subsets to not be added to viewers when adding a
dataset with already existing subsets. [218]

- Fixed compatibility with Qt5. [212]

- Fixed a bug that caused session files created previously to not be
openable. [213, 214]

- Fixed a bug that caused 3D selections to not work properly. [219]

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* Fix selection in scatter plots when categorical data are present. [727]

-------------------

* Fix loading of plugins with setuptools < 11.3 [699]

* Fix loading of plugins when using glue programmatically rather than through the GUI [698]

* Backward-compatibility fixes after refactoring data_factories [696, 703]