Improved tag handling

Now tag counting reflects whether archived cards are shown or not.
Also available the option to select all untagged cards, with matching counter.
Card deletion is now broken, while I found a way to handle the confirmation dialog (see DialogBox component)

frontend/delta/scss/core/layout.scss

@@ -49,6 +49,8 @@
 	
 	.showArchivedCards {
 		@include flex(none);
+		
+		cursor: pointer;
 	}
 }