The "Switch to the last used keyboard" is renamed to "Switching between
input methods" and allows to select "Switch to last used", which was the
default in older releases.

* Add option 'Space bar slider sensitivity'

* Fix slider moving the cursor twice at the beginning

The slider was generating two events when first activated.
Since 2bed42857.

* Make slider less sensitive for the first step

This moves the second slider step approximately 40% further and takes the
new sensitivity option into account.
Allows moving the cursor by one spot more easily.

The number row option is changed into a ListPreference and controls whether the number row contains symbols or not.

Co-authored-by: Joey Schaff <j@jaoh.xyz>