Cleanup: trailing space & tabs to spaces

add_mesh_extra_objects/add_mesh_gears.py

greasepencil_tools/box_deform.py

greasepencil_tools/prefs.py

greasepencil_tools/timeline_scrub.py

io_anim_bvh/import_bvh.py

io_export_dxf/export_dxf.py

io_import_dxf/dxfgrabber/dxfentities.py

io_scene_x3d/import_x3d.py

mesh_looptools.py

mesh_tools/mesh_relax.py

pose_library/gui.py

precision_drawing_tools/pdt_command.py

precision_drawing_tools/pdt_command_functions.py

precision_drawing_tools/pdt_design.py

precision_drawing_tools/pdt_exception.py

precision_drawing_tools/pdt_functions.py

precision_drawing_tools/pdt_library.py

precision_drawing_tools/pdt_menus.py

precision_drawing_tools/pdt_msg_strings.py

precision_drawing_tools/pdt_pivot_point.py