[sfm] colorize tracks: clamp pixel coordinates because feature/marker centers could be outside the image
[sfm] colorize tracks: clamp pixel coordinates because feature/marker centers could be outside the image

CCTags markers can be detected with large occlusions and the center of
the markers can be outside of the image.

poparteu/openMVG,poparteu/openMVG,poparteu/openMVG,poparteu/openMVG