给touchpad启用了circle scrolling还有two-finger scrolling
很早就知道synaptics的circle scrolling，正好刚才在改xorg.conf时想到了，查看了一下wiki，嘿嘿
circle scrolling:
Section "InputDevice"
...
Option "CircularScrolling" "on"
Option "CircScrollTrigger" "0"
...
EndSection
0及可能的选项的含义：
0 All Edges
1 Top Edge
2 Top Right Corner
3 Right Edge
4 Bottom Right Corner
5 Bottom Edge
6 Bottom Left Corner
7 Left Edge
8 Top Left Corner
two-finger scrolling:
Section "InputDevice"
...
Option "VertTwoFingerScroll" "true" # vertical scroll anywhere with two fingers
Option "HorizTwoFingerScroll" "true" # horizontal scroll anywhere with two fingers
Option "EmulateTwoFingerMinZ" "120" # this may vary between different machines
...
EndSectione
实际应用中，感觉后一个比前一个更加实用
