cleanup header files and add util folder
Update ifdefs for disabling widgets
Autodetect dependencies and add override flags

Closes #9
Fix missing include for wklog
Add external IP widget
Automatically detect length of widget array
Add dbus checks to autoconf
Add notification daemon support

Based on ntylo/simplenotifydaemon, but simplified since queueing is
handled by the theme.

Ref #17
Closes #2 (but needs to be implemented in theme)
Fix error in external IP widget