Resolve "Fix warning on MSVC"

Changed onlyVisible-Set to be a set of size_t to reduce the number of conversions.

The other warnings were 'fixed' by just applying an explicit cast.

Closes #296 (closed)

include/manualTrackpointMover.h

@@ -30,7 +30,7 @@ public:
     bool selectTrackPoint(
         const QPointF       &pos,
         const PersonStorage &personStore,
-        const QSet<int>     &peds,
+        const QSet<size_t>  &peds,
         const FrameRange    &range);
     void moveTrackPoint(const QPointF &pos, PersonStorage &personStore) const;
     void setTrackPoint();