Fix BlackMisc header includes

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

refs #630

src/blackmisc/pixmap.cpp

@@ -7,11 +7,19 @@
  * contained in the LICENSE file.
  */
 
-#include "pixmap.h"
+#include "blackmisc/pixmap.h"
+#include "blackmisc/statusmessage.h"
+
 #include <QBuffer>
 #include <QFile>
+#include <QIODevice>
+#include <QReadLocker>
+#include <QWriteLocker>
+#include <QtGlobal>
 #include <tuple>
 
+
+
 namespace BlackMisc
 {
     CPixmap::CPixmap(const QPixmap &pixmap) : m_pixmap(pixmap), m_hasCachedPixmap(true)