Show in vignette using vectorized COMIDs

[mhweber]

Wrap the passing of a data.frame column of COMIDs to a vectorized list of COMIDs happen within the function - the process I currently show in the Applications vignette: comids <- [paste](https://rdrr.io/r/base/paste.html)([as.integer](https://rdrr.io/r/base/integer.html)(flowline_nldi$UT_flowlines$nhdplus_comid), collapse=",",sep="")