Imagedata

Fixed
* MyPolygonSelector.__init__(): define self._polygon_complete.
* Viewer.grid_from_roi(): Set input_order='none' for resulting mask when follow is False.
* Series.tags: Ensure that tag lists are always Numpy arrays.
* Series: Handle properly the situation where a template has wrong number of slices or tags.

Changed
* Improved reading of DICOM files. Each file is read once only.

Added
* Support for Python 3.10.
* Added documentation example using Series and FSL MCFLIRT.
Fixed
* Fixed importlib_metadata handling for Python before 3.8.

Fixed
* Header.__make_DicomHeaderDict_from_template(): Catch IndexError exception when template size does not match data size.
* Documentation updates.

Added
* Support for pydicom version 2.3.
Changed
* Do not scan all local subdirectories when looking up a specific file.
* Removed setup.py.
* AbstractPlugin.read(): Use try..finally to ensure files are closed.
* FilesystemArchive: Do not maintain a cache of local files.
Fixed
* Using relative imports for internal imagedata modules.

Fixed
* Specify exact python versions supported.
* Verify that template axes are adjusted to present data.
* Refactor calculation of smallest/largest pixel value in image/series.
* image_data.calculator: When no indirs arguments, calculate a new image, optionally with template and geometry given.
* Series: Set default header when input is np.ndarray.
* ITKPlugin.get_image_from_numpy(): return image as np.ndarray, not itk matrix.
* Header.set_default_values(): Set default geometry.