add detection/tracking range config in config class and files.

change LidarViewerMain2D, it takes dataset filename as input
-make a base class for LidarGLViewer in velodyne2D inherited by
LidarGLViewerForDetection and LidarGLViewerForTracking
-add configuration for termination condition, change in TrackConf.java
and Track.java
-change LidarFrame.Min_Range to be 0.5, which was 3 before and was the
cause of the occlusion for side passing vehicles.
-add smallCompFilter in ScanFactory.java which clean up the salt and
pepper around vehicles.
-clean up codes, add comments