Created attachment 269429 [details] [review]
Restore smooth scrolling on MacOSX

Currently smooth scrolling using touchpad is not useable on MacOSX. Even very small movement in touchpad results in very large shifts in textview or treeview. 
The reason of this behavior is that in gtkscrollingwindow. c; gtk_scrolled_window_scroll_event() the precise scroll deltas are handled the same way as deltas from mouse wheel. Touchpads of Macs now are quite good at determining xy position of finger, and each such event results in scroll by 3-6 lines in textview (depending on window size). So, instead of smooth scrolling we have quantitized and extremely fast scrolling.
In order to restore smooth scrolling one can apply attached patch. Not sure if it will work equally well on all platforms, but on Mac it works nicely.