TableViewColumn: make resizing easier on touchscreens
TableViewColumn: make resizing easier on touchscreens

Hitting the boundary between the columns is hard with a finger.

Change-Id: I1f2fd87dd87ec8f04dd3fbf4e58b7c6200bc493c
Reviewed-by: Jens Bache-Wiig <9cea9d70b08f8210134ec5959114f72bad51ed1d@digia.com>

drgvond/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols,mizukusak/qtquickcontrols,mizukusak/qtquickcontrols,drgvond/qtquickcontrols