Step 1: Go back to a single control map.

Break save/load for now, it will be redone.
Step 2: Multiple inputs can be mapped per psp key now, and save load works.
Step 3: Replace current key mapping dialog with a list-based one which is much more workable.
Merge branch 'master' into better-controlmap
Fix analog axis names. Make L2/R2 on x360 controllers analog.

Also slightly nicer behaviour - don't create empty mapping, instead ask for mappings immediately.
Fix up/down/left/right ordering for analog sticks
Let the user escape the controls dialog with the global back button (Esc on PC)
Merge pull request #3202 from hrydgard/better-controlmap

Better control mapping