It was globally disabled in ab71599ea1af1ea5042e35502e9aa722cc4ab51e

However most of the time we do not care for intermediate motion
events, and forcing to process them only causes unnecessary
performance overhead.

Fix https://gitlab.com/inkscape/inkscape/issues/496

- avoid unnecessary internal usage of desktop coordinates, e.g.
  in SpellCheck::compareTextBboxes
- document whether a function argument is in document  or desktop
  coordinates, e.g. for SPDocument::getItemsInBox

Closes #340

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- The https://opensource.org/licenses/BSD-2-Clause

Crediting me will be nice, but not mandatory, and you can change the licence
of the project without needing my permission.

This makes the code a lot less readable and greppable for no reason.