[Launcher] Quit does not always exit the application

[Dario Ruellan]

What I expect:
Selecting "quit" from the quicklist on the launcher, should always exit the app.

What I get:
Some applications that have a "hide" option, they close the main window but remain active on the background.

Test case:
Open Rhythmbox and play a music track.
Right click on the launcher icon and select "quit".
The music keeps playing.
You must open Rthymbox and select "quit" from the "music" menu to effectively close it.

I feel that "quit" on the launcher should be a shortcut for the "quit" option on the app menu, and not a mimic of the close button of the window.
Background apps as Rhythmbox or Banshee should be terminated when using the launcher quicklist option.

Ubuntu: 12.04 LTS
Unity: 5.16.0