Started to implement track labeling class. AbstractTracks class needs to
be upgrades, so starts with this.
AbstractTracks: not extending HashMap anymore but has HashMap as a field
value. Generic type of this class as <Integer, V extends AbstractTrack>
Introduced.
debugged failure associated with changes in the AbstractTracks.
Labeling of nucelus working. 
Watershed threshold value now in facade.
working fine. 1. some problems with oversegmented nucelus 2.
interpolation of vacant nodes should be implemented.