gm.tscol make a bar plot in time serie format. Graphic models function family make graphic creation
easy, is recommended for new programers, they have less and easyful parameters then p.tscol but
the graphic customize is more limited . The data don't need be a ts object.
# NOT RUN {v=data.frame("x"=seq.Date(as.Date('2020-01-01'),
to = as.Date('2020-04-01'),by='month'),"y"=c(5,3,7,2))
gm.tscol(v,1,2,title="Simple example",ntimes=3)
# }