Move TerminalDisplay::HAVE_TRANSPARNCEY into its own dedicated class

TerminalDisplay.h is a big header. It is not good for several files to
include that big header only in order to use one of its static member.

src/WindowSystemInfo.cpp

@@ -0,0 +1,28 @@
+/*
+  Copyright 2012 Jekyll Wu <adaptee@gmail.com>
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License as
+  published by the Free Software Foundation; either version 2 of
+  the License or (at your option) version 3 or any later version
+  accepted by the membership of KDE e.V. (or its successor appro-
+  ved by the membership of KDE e.V.), which shall act as a proxy
+  defined in Section 14 of version 3 of the license.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program. If not, see http://www.gnu.org/licenses/.
+*/
+
+// Own
+#include "WindowSystemInfo.h"
+
+using Konsole::WindowSystemInfo;
+
+bool WindowSystemInfo::HAVE_TRANSPARENCY = false;
+
+