New file output.h with output flags and modes.
--full parameter also for cgls and loginctl.
Include 'all' parameter in flags (show_cgroup_by_path, show_cgroup,
show_cgroup_and_extra, show_cgroup_and_extra_by_spec).
get_process_cmdline with max_length == 0 will not ellipsize output.
Replace LINE_MAX with 0 in some calls of get_process_cmdline.
[zj: Default to --full when under pager for clgs.
Drop '-f' since it wasn't documented and didn't actually work.
Reindent a bit.
]