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/libs/utils/buildablehelperlibrary.cpp

@@ -28,20 +28,11 @@
 ****************************************************************************/
 
 #include "buildablehelperlibrary.h"
+#include "hostosinfo.h"
+#include "synchronousprocess.h"
 
-#include <QFileInfo>
-#include <QCoreApplication>
-#include <QHash>
-#include <QProcess>
 #include <QDir>
 #include <QDateTime>
-
-#include <utils/environment.h>
-#include <utils/fileutils.h>
-#include <utils/hostosinfo.h>
-#include <utils/synchronousprocess.h>
-
-#include <QDesktopServices>
 #include <QDebug>
 
 namespace Utils {