This commit adds basic gesture support to WEC7 Qt builds, which
enables developer to create custom gesture recognizers based on mouse
events.
Note that QTouchEvents are not yet generated in WEC7 Qt builds, so
recognizers based on those cannot be created.
Task-number: QTBUG-22517
Change-Id: Ic6218500b28b78ca8edec3edebd00d84c308a182
Reviewed-by: Joerg Bornemann <joerg.bornemann@nokia.com>