def _calculate_column_offsets
      @coffsets = []
      total = 0

      #@chash.each_pair { |i, c|
      #@chash.each_with_index { |c, i|
        #next if c.hidden
      each_column {|c,i|
        w = c.width
        @coffsets[i] = total
        c.offset = total
        # if you use prepare_format then use w+2 due to separator symbol
        total += w + 1
      }
    end
def _calculate_column_offsets
      @coffsets = []
      total = 0

      #@chash.each_pair { |i, c|
      #@chash.each_with_index { |c, i|
        #next if c.hidden
      each_column {|c,i|
        w = c.width
        @coffsets[i] = total
        c.offset = total
        # if you use prepare_format then use w+2 due to separator symbol
        total += w + 1
      }
    end
This calculates and stores the offset at which each column starts.
 Used when going to next column or doing a find for a string in the table.
 TODO store this inside the hash so it's not calculated again in renderer