Empty columns?

[delaneyj]

I'd like to have columns that contain no data to be used as tags, Is a struct{} or other empty value possible? Bool where its always is true could be an option but seems wasteful sense you already have the concept of bitsets.

EDIT:
Reading through the code it looks like Bool is actually doing what I thought it should and not using a Go bool but using the bitset. Might be worth explaining in the docs and/or the comments on the type.