[polybar] Add pomo timer as git submodule

Using [jsspencer/pomo](https://github.com/jsspencer/pomo) as the timer
of choice. It is simple, it works well, and it uses a very elegant way
of tracking the time.

I can think about implementing my own version later, but this will
handily suffice for now.

Polybar script will now limit the pomo timer to a single 'running'
instance containing the notification function, by putting its running
instance PID in a lockfile and killing it before restarting or changing
the timer.

Added running and paused tomato icons; as well as break coffee icon.
Removed display of seconds, unless the last minute of a timer is
running.

polybar/.config/polybar/scripts/poly-papersdue

@@ -1,7 +1,7 @@
 #!/usr/bin/env sh
 
 while true; do
-  all="$(bib-due -u 'fri this week' | wc -l)"
+  all="$(bib-due -u 'fri this week' -p3 | wc -l)"
   required="$(bib-due -u 'fri this week' -p1 | wc -l)"
 
   # add polybar formatting to color required readings red

polybar/.config/polybar/scripts/poly-pomo

@@ -0,0 +1,41 @@
+#!/usr/bin/env sh
+
+run_notify() {
+  pomo notify &
+  PID_NOTIFY="$!"
+  echo "$PID_NOTIFY" >"${XDG_RUNTIME_DIR:-$HOME}"/.running-pomo.lock
+}
+
+# create background notify process; close it when this process  is killed
+close_notify() {
+  lockfile="${XDG_RUNTIME_DIR:-$HOME}"/.running-pomo.lock
+  [ -f "$lockfile" ] && kill "$(cat "$lockfile")"
+  kill "$PID_NOTIFY"
+  rm "${XDG_RUNTIME_DIR:-$HOME}"/.running-pomo.lock
+}
+trap close_notify EXIT
+
+restart_notify() {
+  close_notify
+  run_notify
+}
+
+if [ -z "$1" ]; then
+  run_notify
+  while true; do
+    display=$(pomo clock)
+    # replace W (work)
+    #         B (break)
+    #         P (paused) with pomodoro symbols
+    # remove seconds *except for* when 00 minutes reached
+    display=$(echo "$display" | sed -e 's/P.*$/  /;s/W/ /;s/B/ /;/00:/! { s/:[[:digit:]]\+$// }')
+    echo "$display"
+    sleep 1
+  done
+elif [ "$1" = "toggle" ]; then
+  pomo pause
+  restart_notify
+elif [ "$1" = "restart" ]; then
+  pomo stop && pomo start
+  restart_notify
+fi