Added script for libnotify upon receiving mail in claws-mail.

* dwm patches are now in an array and build() cycles through them.
  => idea by Unia (https://github.com/Unia/DWM/blob/master/PKGBUILD)
* build() now contains variable for indicating whether to fully rebuild
  or not.
* dunst has borders now.
* Enabled wallpaper cycling again.
Follow-up for last commit (nitrogencycle).

* Check if cycle directory exists, otherwise ignore.