- fix all `def poll(self)` to `def poll(cls)` to let it fit class method name convention.
- fix wrong progress counter when importing virtools file.
- add light support when importing virtools file.
- add corresponding conflict strategy and resolver for light.
- disable bmx import/export temporaryly
- optimize the ui display of importing/exporting. (use box to organize props)
- place button horizontally, not vertically in virtools material.
- disallow apply in legacy align if no axis selected.
- add applied step counter in legacy alignment.
- add feedback for reseting bme material/component. (add a message box to show success)
