FixedWidth writer.
Test of file name length.
Padding file name string which is input to the table writes to 100 characters.  This is a work around to prevent astropy.io.ascii from truncating strings as the summary table is read and written.  After the first image is written to the table, the next one reads that table.  The type of that column then seems to be chosen to be the length of that first string, so no subsequent filename can be longer than the first without getting truncated.
Now read in table using a converter in ascii.read.
Merge branch 'feature/New_Writer_for_Summary_File' into develop