Remove the hardcoded (and way too small) scroll threshold (the distance moved in pixels before we think the users wants to scroll) and replace it with something based on the actual DPI of the screen.
On Android we call the API for that, on other touchscreens we reimplemented Android's formula (as of 2.2) and calculate it.
Flyspray: 11727
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@28548 a1c6a512-1295-4272-9138-f99709370657
