resize for multiple-objects-in-single-label-file error for kitti dataset

[shaojun]

Hi,

Thanks for the great repo.

I have a kitti label file like:

closedsign 0.0 0 -1 403 0 460 22 -1 -1 -1 -1 -1 -1 -1 closedsign 0.0 0 -1 401 16 461 86 -1 -1 -1 -1 -1 -1 -1

after cvdata_resize it, the two line will combined into single one line, like:

closedsign 0.0 0 -1 403 0 460 22 -1 -1 -1 -1 -1 -1 -1closedsign 0.0 0 -1 401 16 461 86 -1 -1 -1 -1 -1 -1 -1

could you check?