Updates to the Zsh pkgtools.

Updates to the Zsh pkgtools.

Mostly this is to do with having groups span multiple lines in
/etc/group.  Toward that end, parsing /etc/group is not done anymore.
To get at the 'install' group members we use groupmems(8) (via sudo).

The output of Lpkg() was cleaned up.  Yup, I just discovered
column(1). :-)

Two new functions:
  dpkg() -- Print a package's short description
  Dpkg() -- Print a package's long description.

The old dpkg() to show a package's dependencies has been renamed to pkgdeps()

	* etc/pkgusr/zsh/_zsh-pkgtools (_pkgtools_users): Use groupmems
	instead of parsing /etc/group.

	* etc/pkgusr/zsh/zsh-pkgtools: Whitespace reformat.  Tabs are 8
	chars wide, but in shell-scripts I like 4 char indents.
	(pkgdeps): New, renamed from 'dpkg'.
	(dpkg): Now prints a package's short description.
	(Dpkg): New, print a package's long description.
	(pkglst): New.  Saves package list to a var, $PKGLST
	(fpkg): Use $PKGLST. Add `-E' grep option.
	(lpkg): Parse $PKGLST instead of /etc/group.
	(Lpkg): Parse $PKGLST instead of /etc/group, use column(1) for
	cleaner output.
	(pkg_install): Call pkglst() to update $PKGLST
	(pkgwant): Use $PKGLST instead of calling lpkg()

Signed-off-by: Steve Youngs <steve@steveyoungs.com>