recent changes to plot.phylo / phylogram.plot have side effext

[KlausVigo]

Hi Emmanuel and Martin (@emmanuelparadis, @ms609), the recent changes you made to plot.phylo and phylogram.plot seem to cause side effects.
I'll try to fix this but you want to check if there are other packages affected.

I get an error during R check with github actions: 
> checking examples ... ERROR
Error:   Running examples in ‘phangorn-Ex.R’ failed
  The error most likely occurred in:

  > base::assign(".ptime", proc.time(), pos = "CheckExEnv")
  > ### Name: cladePar
  > ### Title: Utility function to plot.phylo
  > ### Aliases: cladePar
  > ### Keywords: plot
  > 
  > ### ** Examples
  > 
  > 
  > tree <- rtree(10)
  > plot(tree)
  > nodelabels()
  > x <- cladePar(tree, 12)
  > cladePar(tree, 18, "blue", "blue", x=x, plot=TRUE)
  Error in segments(x0v, y0v, x0v, y1v, col = color.v, lwd = width.v, lty = lty.v) : 
    invalid line type: must be length 2, 4, 6 or 8
  Calls: cladePar -> plot -> plot.phylo -> phylogram.plot -> segments
  Execution halted

Cheers, Klaus

[emmanuelparadis]

Hi Klaus, Thanks for the fix! The details can be found at ?par in the section "Line Type Specification". I have accepted your PR. Cheers, Emmanuel