restoring TR as marker and readable from fort.3;
restoring TR as marker and readable from fort.3;

At the same time:
   * corrected calls to checkRT;
   * initRT initialises also ape(1) and ape(2);
   * updating format of dumping aperture markers;
   * better initialisation of tmpflts array when parsing aperture marker;

SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack,SixTrack/SixTrack