Gdspy

Version 1.6 will be the last major release of Gdspy, with development focused only on bug fixes.
Development will continue in a new project: [Gdstk, the GDSII Tool Kit](https://github.com/heitzmann/gdstk).
Users are encouraged to move from Gdspy to Gdstk: although their API is not 100% compatible, the new module should be familiar enough to allow a quick transition.

Change log:
* Added support for element properties.
* Added transformation support to Cell.copy.
* Layer/datatype filtering in get_polygons for Cell, CellReference and CellArray.
* Layer/datatype filtering in LayoutViewer.
* Removed global cache _bounding_boxes. Only cells cache their bounding boxes.
* Bug fixes (thanks Daniel Hwang for the contributions).
* Bug fix in Cell.copy where the whole dependency tree would be copied on a deep copy creation.

- Added support for BOX elements when loading a GDSII file.
- Bug fix for 120

This version of Gdspy comes with many changes and bug fixes!

Most noteworthy are the new [`Cell.write_svg`](https://gdspy.readthedocs.io/en/stable/reference.html#gdspy.Cell.write_svg) method and the rework of `GdsLibrary` to deprecate the use of a `current_library`, which cause many problems for new users in IDEs.

Take a look at the History of changes for [this version](https://github.com/heitzmann/gdspy/#version-15-dec-20-2019) in the README for a full list of what's new.

Bugfix release for 107.

This is a minor release containing only bug fixes for v1.4.1.

This is a minor release containing only bug fixes for v1.4.