Bug fixes and, minor enhancements

Fixes: #1583, #1552, #1550, #1521, #1518, #1513, #1510, #1417, #1550.
Also fixed some undocumented errors that caused the span["origin"] to be incorrectly set in corner cases.

Added new items "orientation" and associated transformtion matrix to the output of fitz.image_properties(), which contains EXIF data of supporting image files.

A new method Document.xref_copy() allows making xref objects duplicates of each other.