DOC: Demo Header repr and str.
DOC: Demo Header repr and str.

NSLS-II/docs,NSLS-II/docs,danielballan/docs,waynelewis/nsls-ii-docs,tacaswell/docs,waynelewis/nsls-ii-docs,NSLS-II-SRX/docs,NSLS-II-SRX/docs,danielballan/docs