Allow OS synthesized mouse events by default on Windows

https://codereview.qt-project.org/#change,66028 fixes Quick2 apps so
there will be no need to ignore mouse events synthesized from touches
by the OS. The mousefromtouch plugin parameter is changed to
nomousefromtouch since mousefromtouch becomes the default.

This will restore the OS-provided functionality, like translating
tap-and-hold to right clicks, for Quick1 and widget apps.

Change-Id: I5554a91a54365b9c72c3ad304010b9fc4e53ab24
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>