2D Feature tracking

2D Feature tracking.

Normal classes:

PointTrackC	Information on a single point track.
PointTrackModelC	Tracking information on a single point.
PointTrackerC	Point tracker.

Normal functions:

operator <<(ostream &,const PointTrackC &)	Save to ostream.
operator >>(istream &,PointTrackC &)	Load from istream.