MER: Revert "Revert "Improve filtering of touch and mouse events.""

This reverts commit 7f1067c97f55da45ffe3da7ec91ad32a2bcef255.

This completely breaks touch handling on Sailfish (pinch zoom becomes wildly
unpredictible).

Conflicts:
	src/imports/location/qdeclarativegeomap.cpp
	src/imports/location/qdeclarativegeomapgesturearea.cpp

Change-Id: I4903f4bedabc49250f7c2dd4a019f3a5a1845787