touchscreens, instead of touchpad's where this driver was intended
for. This is working perfectly on my sabreLite iMX6 board with a Nit6X
multitouch touchscreen. All the mulitouch events are still worlking properly.
Remark: There is no scaling on the absolute input coordinates so both
resolutions should match.
Updated with remarks from BlueDragonX
generic: move storage into struct MTouch
mtrack: emit moves between button-up en button-down

When move come after button-down, then buttons may be triggered
on the wrong spot, because the pointer needs to move first.
When move come before button-up, then dragging does include the last
move, when mtrack found a button-up. This apperently happens on the next
button-down?
gestures: introduce tap_buttonnr()
touchscreen: implement single finger direct button

This makes using mtrack on a touchscreen more pleasant.
The tapping gesture, which comes from a trackpad, is not needed
here to indicate, the touchscreen positions absolutely.
touchscreen: add single_finger option

Make the single_finger behaviour configurable.
Until it has proven to respect all other gestures,
I must be able to turn it off on my touchscreen.
generic: fix warnings
generic: fix illegal access
cross-compile: remove fixed host include directories