[notify] add initial freedesktop notify support
Merge branch 'notification'
Merge branch 'master' into notification
Use NO_INSTALL argument in freedesktop_notify to generate headers even if the addon is disabled.

Conflicts:
	src/module/CMakeLists.txt
	src/ui/classic/MenuWindow.c
[freedesktop-notify] use private codegen to support long arg list. (It compiles...)
[notify] line wrap, indent, TODO
[notify] clean up
[notify] id handling
[notify] typo, close notification