doxygen: update to new version

Run doxygen -u so we get a new doxyfile without the old deprecated
options.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
gitignore: ignore tar.xz

We now use xz-compression (way better than bz) so ignore those tarballs
from "make dist".

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: split info and error messages apart

We now introduce a second text-line above the error-message line which
is used for informational messages that are not considered an error.

This avoids overwriting errors which could be quite important for users
to debug occuring problems.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: cut error/info messages if too long

We now write messages into a buffer and cut them before printing them.
This avoids writing across screen bounds. We also correctly clear the
extended error region if in MODE_EXTENDED.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: print warning if not run with root privs

We often need root privs to access evdev char-devices and sysfs some
attributes. Hence, warn the user if they run xwiishow without such
privileges.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
lib: fix xwii_iface_open() error handling

Fix few copy/paste typos and a possible errno-overwrite.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: fix print_error() mvprintw() args

Ugh! I forgot to adjust print_error() according to print_info().. Fixed
that now so the arguments are correctly parsed.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: print errors if ifaces cannot be opened

If we toggle an interface and the xwii-call fails, we now print an error
(as we already did for MP errors).

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
xwiishow: automatically open all interfaces

We now open all available interfaces during startup and on every hotplug
event. This seems to be quite reasonable for a debug application like
xwiishow.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>