WelcomeScreen: Implementing proper search lexer/parser for the lineedit.

Now copes with quotes and "tag:" prefixes.

Change-Id: I348e533ab290242fd05a034a2912cc95f0a9a3da
Done-with: Roberto Raggi
Reviewed-on: http://codereview.qt.nokia.com/2038
Reviewed-by: Daniel Molkentin <daniel.molkentin@nokia.com>

src/plugins/welcome/welcomeplugin.cpp

@@ -63,7 +63,7 @@
 #include <QtDeclarative/QDeclarativeEngine>
 #include <QtDeclarative/QDeclarativeNetworkAccessManagerFactory>
 
-enum { debug = 0 };
+enum { debug = 1 };
 
 using namespace ExtensionSystem;