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/annotateditemdelegate.cpp

@@ -29,12 +29,7 @@
 
 #include "annotateditemdelegate.h"
 
-#include <QSize>
-#include <QModelIndex>
-#include <QStandardItemModel>
 #include <QPainter>
-#include <QStyle>
-#include <QStyleOptionViewItemV4>
 #include <QApplication>
 
 using namespace Utils;