* input: fixed position-offset, time and time-offset.
* hotkeys: never _never_ use demux_Control outside of src/input/ (it's
completely broken, there is a lot more things to do), all interfaces
have to use var_Get/Set (time(-offset), position(-offset), state,
rate(-slower|-faster)... ).
Btw, input_SetStatus, input_Seek, input_Tell, input_ChangeArea,
input_ToggleES, will be quickly obsolete and removed(at least
unavailable for intf), so we should convert remaining interfaces (ie all
except wx, osx, rc, http, hotkeys).