Empty block for table columns

[bradgessler]

The Table component should support empty blocks, which would make this work:

render TableComponent(items: Interviewer.all).new do |table|
  table.column("Interviewer") { show(_1, :name, style: "white-space: nowrap;") }
  InterviewTime.all.each do |time|
    table.column(time.name) # This throws an error because it wants a block
    table.column(time.name) { } # This does work, but its ugly passing an empty block. Make it behave this way.
  end
end