Initialized empty files for tray implementations.

Telegram/SourceFiles/tray.cpp

@@ -0,0 +1,15 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop application for the Telegram messaging service.
+
+For license and copyright information please follow this link:
+https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
+*/
+#include "tray.h"
+
+namespace Core {
+
+Tray::Tray() {
+}
+
+} // namespace Core