Auto-enable smooth scrolling when enabling continuous scrolling

Created by: JensErat

Smooth scrolling feels nice in continuous scrolling mode (I'm using a M705), but in the stepped mode it makes the scroll wheel rather useless, as it already registers minor movements, making middle-clicks without scrolling very difficult. Automatically enabling smooth scrolling when switching to continuous mode (and disabling it vice-versa) would be a great improvement.

xev prints events when changing to/from the continuous mode, so it should be possible to attach some configuration change to it:

ButtonPress event, serial 32, synthetic NO, window 0x4a00001,
    root 0xaa, subw 0x0, time 113403970, (389,619), root:(3593,639),
    state 0x10, button 20, same_screen YES

ButtonRelease event, serial 32, synthetic NO, window 0x4a00001,
    root 0xaa, subw 0x0, time 113404282, (389,619), root:(3593,639),
    state 0x10, button 20, same_screen YES