added battery stuff

i3/toggle_battery_display.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+# toggles display mode (percent <-> time) for the battery module
+state_file="${XDG_CACHE_HOME:-$HOME/.cache}/polybar_battery_mode";
+current="percent";
+if [[ -f "$state_file" ]]; then
+  current="$(cat "$state_file" 2>/dev/null | tr -d '\n')";
+fi
+if [[ "$current" == "percent" ]]; then
+  echo "time" > "$state_file";
+else
+  echo "percent" > "$state_file";
+fi