r23941 2024-03-27 dhuby FIX: Broken legacy unoconv mode [q13053]

M /trunk/include/preview_preprocessing.php
r23940 2024-03-27 dhuby NEW: Support for unoconvert, successor to unoconv [q13053]

M /trunk/include/general_functions.php
M /trunk/include/preview_preprocessing.php