ISM Metadata files: Remove Frame Index

The file for the ISM metadata looks as follows:

0,0.00,0.00,1.00,0.00,1.00
1,4.80,0.00,1.00,0.00,1.00
2,9.60,0.00,1.00,0.00,1.00
3,14.40,0.00,1.00,0.00,1.00
4,19.20,0.00,1.00,0.00,1.00
5,24.00,0.00,1.00,0.00,1.00
...

The first column contains the frame index, which is basically not used (only for sanity checks), and makes e.g. editing of these files hard.

It is proposed to remove this column