Onetime functionality

[budRich]

this patch adds -o option. If set, xnotify will terminate after the first notifications timeout is reached.

with this functionality together with #1 one can achieve a simple yet dynamic notification center.

f.i. One can have a normal xnotify process reading from a fifo:

mkfif /tmp/xnotify.fifo
cat /tmp/xnotify.fifo > xnotify -G SE &

But also spawn context specific onetime notifications at the same time:

#!/bin/bash
[[ everything_beautiful = must_die ]] && { echo "its true you know" | xnotify -c '#FF0000' -s 5 -o -G NW   ;}
echo notification has been shown

It can also be used to "pause" execution of a script (like example above).

[phillbush]

Nice addition.
I'm gonna merge it and do some modifications, in special, remove the onetime flag from the config structure since it is not set on config.h at compile time, but on command line option at runtime, and adapt the indentation and comment style to the rest of the program.

One downside of this -o option is that it does not queue the notifications, so if you invoke two xnotify instances at the same time the notifications will overlap one another. Cating a fifo into xnotify and echoing a line on demand queue the notifications, since only a single xnotify instance would be involved.

[phillbush]

I removed xnotify.h accidentally, I was supposed to just remove a line...

[phillbush]

I removed the -o flag and made the one-time behavior the default behavior for xnotify.
(That is, now when you echo Hello World | xnotify, xnotify will exit when the notification is done).

[budRich]

sweet!