fix include style relating to cplusplus libraries

... and adjust INCLUDEPATH accordingly.

while i'm at messing with include statements, also re-order the include
blocks according to policy and sort them within bigger blocks.

Change-Id: I7762abfd7c4ecf59432b99db2f424e4fa25733a5
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/cpptools/cpptoolseditorsupport.cpp

@@ -28,18 +28,18 @@
 ****************************************************************************/
 
 #include "cpptoolseditorsupport.h"
+
 #include "cppcompletionsupport.h"
 #include "cpphighlightingsupport.h"
 #include "cppmodelmanager.h"
 
 #include <coreplugin/idocument.h>
-
 #include <texteditor/itexteditor.h>
 #include <texteditor/basetexteditor.h>
 
-#include <AST.h>
-#include <ASTVisitor.h>
-#include <TranslationUnit.h>
+#include <cplusplus/AST.h>
+#include <cplusplus/ASTVisitor.h>
+#include <cplusplus/TranslationUnit.h>
 
 #include <QTimer>