lib: Fixed bad node copy, modified token regex

lib: Fixed bad node copy, modified token regex

When building argv for matched command, only the
last node was being copied to argv; the rest were
added by reference. Additionally the regex for
certain tokens was too restrictive and disallowed
characters allowed by the old parser; these have
been reinstated.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>