Clean headers in QmlJs.

Ran script to remove inludes on a trial-and-error basis and
manually corrected it (Parser excluded).

Change-Id: I5ec6e1076430009bb72094411b2c3386f8bea548
Reviewed-by: Aurindam Jana <aurindam.jana@digia.com>

src/libs/qmljs/qmljsicons.h

@@ -32,7 +32,8 @@
 
 #include <qmljs/qmljs_global.h>
 #include <qmljs/parser/qmljsast_p.h>
-#include <QIcon>
+
+QT_FORWARD_DECLARE_CLASS(QIcon)
 
 namespace QmlJS {