Fix BlackMisc header includes

* Include only what is used
* Use forward declaration when possible
* Sorted includes

refs #630

src/blackmisc/atomicfile.h

@@ -12,9 +12,14 @@
 #ifndef BLACKMISC_ATOMICFILE_H
 #define BLACKMISC_ATOMICFILE_H
 
-#include <QFile>
 #include "blackmisc/blackmiscexport.h"
 
+#include <QFile>
+#include <QFileDevice>
+#include <QIODevice>
+#include <QString>
+#include <exception>
+
 namespace BlackMisc
 {
     /*!