[Rd] boxplot graphical arguments (PR#6832)

[arnima at u.washington.edu]

Dear r-bugs,

I'd like to be able to draw boxplots with solid or dotted whisker lines.
The lty argument is currently ignored by boxplot(), and indeed hardwired
in bxp().

It's not very difficult to customize these functions to generate various
types of boxplots, but generally it might be an idea to allow the user to
pass a few more graphical arguments to boxplot(). The approach might as
well mimic S-Plus, but still retain the default R look.

Thanks,
Arni

R 1.9.0 on WinXP