First effoct to gobjectify PraghaToolbar.
TODO:
 * Port the rest of buttons and signals.
 * Add volume propertie, and directly bind it with PraghaBackend.
 * Easily can do something similar with keybinder, gnome-media-key, or systrays signals.
 * If I do the same with PraghaPlaylist, PraghaSidebar, etc.. can remove PraghaWindow.
Use signals to show-current-album-art.
Edit current song using signals.
Seek playback clicking on progress bar using signals.
Add volume property to PraghaToolbar, and synchronize this with the Backend.
Remove unused pragha_toolbar_get_volume_button()
Remove a lot of cwin of PraghaToolbar
Add timer-remaning-mode as property of PraghaToolbar.
Add explicit pragha_toolbar_set_image_album_art() and move some code.
Unfllscreen using signals.
D'OOOOh!.
Fix delay of show the seek event in gui.
Fix delay when change to time remaning mode..
Use g_signal_connect_swapped to avoid one line wrapers..
Clean a little and silent warning when compiling
Remove all code to get the album art from pragha-toolbar.c