Clean headers in Utils.

Forward-declare QGraphicsOpacityEffect in DetailsButton,
QProcessEnvironment in Environment, QFileInfo in fileutils,
QUrl in IWelcomePage, FancyLineEdit in PathChooser and
remove unneeded headers.

Change-Id: I7d5f273530dd2059bbdaf0899f0a3bc7e49e8482
Reviewed-by: hjk <hjk121@nokiamail.com>

src/plugins/qnx/pathchooserdelegate.cpp

@@ -32,8 +32,7 @@
 #include "pathchooserdelegate.h"
 
 #include <utils/pathchooser.h>
-
-#include <QLineEdit>
+#include <utils/fancylineedit.h>
 
 using namespace Qnx;
 using namespace Qnx::Internal;