* If an input is configured to some combination of controls that are not
present at all, ignore the setting altogether for the session.
* Fixed relative axes with PORT_RESET not responding to absolute
controls (MT07685).
* Fixed relative axes not responding to an absolute control if the value
doesn’t change every frame (eg. holding a stick against the stop).
* Changed the scaling for absolute controls assigned to relative axes to
make defaults more sane (e.g. arkanoid or spdheat with a joystick).
-frontend: Fixed some localisation issues in Analog Controls menu.
-docs: Added documentation on assigning inputs.