drop debug printf, use glib logging

Index: src/Widgets/gmpc-data-view.vala
--- src/Widgets/gmpc-data-view.vala.orig
+++ src/Widgets/gmpc-data-view.vala
@@ -137,7 +137,7 @@ public class Gmpc.DataView : Gtk.TreeView
         }
         set{
             if(view_mode == ViewType.PLAYLIST) {
-                stdout.printf("Set playlist name: %s\n", value);
+                log(log_domain,LogLevelFlags.LEVEL_DEBUG, "Set playlist name: "+ value);
                 __playlist_name = value;
             }else {
                 error("Cannot set playlist name on non-playlist view.");
@@ -333,7 +333,6 @@ public class Gmpc.DataView : Gtk.TreeView
         for(int i = 0; i < Gmpc.num_plugins; i++){
             if(plugins[i].get_enabled() &&
                     plugins[i].browser_song_list_option_menu(this,smenu) > 0){
-                stdout.printf("adding entry\n");
                 initial = true;
             }
         } 
