## Link to GitHub Issue or related Pull Request, if one exists
n/a
## Description of change
Some crappy DDR soft mats (either USB-based or console pads with crappy
adapters that lack a dedicated "DDR pad mode") use X and Y analog axis
for arrows, which means they cannot cleanly report Up+Down or Left+Right
input.
According to some ancient Stepmania code, a lot of these report a middle
value (value between center and right, for example, for left+right).
Borrow this hack from Stepmania and implement it in spice as analog
input for DDR.
Also, for rawinput/xinput automatic bind scenario, update the logic so
that face buttons are always detected before analog axis / dpads for
consistency. This would help with binding any DDR pads that
simultaneously input face buttons / dpad / analog axis, so that we can
prefer face buttons when detected.
## Testing
I don't have any soft mats that have this, but it was tested with an
xbox controller.