make flags stick when chaining

[mcastorina]

Line specific flags need to be specified for each link in the chain.

e.g. --marker '' is specified twice below

graph sine.csv --marker '' -C | graph cosine.csv --marker ''

It would be easier for the user to make that value "stick" either globally or in subsequent links. At this point I think it is better to have it global so the user can simply add it to the last link instead of the first.

One idea is to add the same named flags but capitalized.

graph sine.csv -C | graph cosine.csv --Marker ''