New Features
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- Add matplotlib like API in `magicclass.plot_api` (55).
- Implement `Points`3D, `Arrows3D` layers and napari-style blending in `magicclass.ext.vispy` (52, 56).
- Implement `impl_preview`, a successor of `mark_preview`, for preview/prerun of method (57).
- Implement `magicproperty` for property like widget creation (58).
- Add `magicclass.logging` submodule for logging in a widget.
Bug Fixes
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- Signals were not connected to `FieldGroup` (51).
- Child `FunctionGui` widgets were invisible (54).
- `range` objects were not formatted in macro.