Hebnix v0.1.8

Add ui.collapsing and hebnix.command, read stock binds from TAInput.ini

Plugins calling ui.collapsing (PfpOverlayV2's settings page) failed with
"attempt to call a nil value (field 'collapsing')". Port it from the
Windows tree together with the rest of the Lua surface that was missing:
hebnix.command.{change_pov, load_replay, seek_replay, set_game_speed,
set_hud_visibility, set_match_paused}.

Also port the TAInput.ini fallback for action binds: the save file only
stores binds the player changed, so stock binds were missing from
hebnix.input action lookups.