Associate MarkerID with person rather than position
At the moment the MarkerID is stored with the position points rather than the person.
This leads e.g. to markerIDs being "interrupted" by the value of -1 if the marker is not recognized in one frame.
.txt-example output:
# PeTrack project: cam8Calib_workingversion1.pet
# raw trajectory file:
# framerate: 50 fps
# z: can be 3d position or height of person (alternating or not)
# id frame x/cm y/cm z/cm markerID
1 349 57.6568 -52.7713 180 998
1 350 55.2305 -50.7363 180 -1
1 351 52.7677 -48.6721 180 -1
1 352 50.2892 -46.4331 180 998
1 353 47.8889 -44.3049 180 -1
1 354 45.4668 -41.9753 180 998
1 355 43.126 -39.7216 180 998
1 356 40.9251 -37.5231 180 998
1 357 39.0034 -35.1863 180 998
1 358 37.1774 -32.9431 180 -1
1 359 35.4607 -30.702 180 -1
1 360 33.9067 -28.5663 180 -1
1 361 32.4698 -26.5273 180 -1
1 362 31.1355 -24.5548 180 -1
1 363 29.8235 -22.3598 180 998
1 364 28.6904 -20.4523 180 -1