fileinfo: Basic structure
fileinfo: Get number of data columns in files

The number of columns minus IF_FUTURE is determined once
and then saved to variables NCOLS_file to be used again.
fileinfo: File lists with -V01 or -V01-V02 suffix

Single or double indices run up to the minimum of file
specific NCOLS_file and global name_LAST_COL variables.
The second macro argument is an additional suffix.
fileinfo: File lists with enumerated plot suffixes

The index runs up to the minimum integer such that name_PLOT_NCOLS
columns are considered per file with a total number of name_LAST_COL
or NCOLS_file columns. The second and third argument of the add_01
macro allow to specify additional suffix parts around the number.
fileinfo: Performance increased by using variables