media library: change data fetch delay to 250ms

src/media_library.cpp

@@ -47,7 +47,8 @@ MediaLibrary *myLibrary;
 
 namespace {
 
-const auto fetch_delay = boost::posix_time::milliseconds(500);
+const auto ml_wtimeout = 250;
+const auto fetch_delay = boost::posix_time::milliseconds(ml_wtimeout);
 
 bool hasTwoColumns;
 size_t itsLeftColStartX;
@@ -422,6 +423,14 @@ void MediaLibrary::update()
 	}
 }
 
+int MediaLibrary::windowTimeout()
+{
+	if (Albums.reallyEmpty() || Songs.reallyEmpty())
+		return ml_wtimeout;
+	else
+		return Screen<WindowType>::windowTimeout();
+}
+
 void MediaLibrary::enterPressed()
 {
 	AddToPlaylist(true);

src/media_library.h

@@ -37,6 +37,8 @@ struct MediaLibrary: Screen<NC::Window *>, Filterable, HasColumns, HasSongs, Sea
 	virtual void refresh() OVERRIDE;
 	virtual void update() OVERRIDE;
 	
+	virtual int windowTimeout() OVERRIDE;
+
 	virtual void enterPressed() OVERRIDE;
 	virtual void spacePressed() OVERRIDE;
 	virtual void mouseButtonPressed(MEVENT me) OVERRIDE;