[Gui] So headers: remove unused includes

- also sort out some headers to be used in precompiled headers
- also move a boost header to precompiled headers

src/Gui/DocumentRecovery.cpp

@@ -27,6 +27,7 @@
 #include "PreCompiled.h"
 
 #ifndef _PreComp_
+# include <boost/interprocess/sync/file_lock.hpp>
 # include <QApplication>
 # include <QCloseEvent>
 # include <QDateTime>
@@ -46,8 +47,6 @@
 # include <sstream>
 #endif
 
-#include <boost/interprocess/sync/file_lock.hpp>
-
 #include <App/Application.h>
 #include <App/Document.h>
 #include <Base/Exception.h>