Improve handing of single-scalar calls to cmd()
Improve handing of single-scalar calls to cmd()

Just pass the entire supplied command line, be it a single scalar or an array,
to system(). It'll do the right thing with it. This gets rid of a spurious
trailing space in debugging output when cmd() was called with a single scalar
as the command argument (leaving @cmdline undefined).

toreanderson/clatd,toreanderson/clatd