Move the cursor further when sliding faster on the spacebar

[Julow]

Might fix https://github.com/Julow/Unexpected-Keyboard/issues/566

The two visible changes are:

• The spacebar slider sensitivity no longer depend on the "Swiping distance" option. This made the cursor harder to control when the option was not set to "Normal". Might be related: https://github.com/Julow/Unexpected-Keyboard/issues/548
• The spacebar sensitivity increases when the finger travels faster. This hopefully increases the range without reducing the precision on short movements.