Fixed MSVC 2012 build.

core/helper.h

@@ -4,7 +4,9 @@
 #include <QString>
 #include <QMap>
 
-class Helper
+#include "core_global.h"
+
+class CORESHARED_EXPORT Helper
 {
 public:
     Helper();
@@ -12,7 +14,9 @@ public:
     static QString replaceByNumbers(const QString &str);
 
 private:
+#ifndef _WIN32
     static const QMap<QString, QString> m_numMap;
+#endif
 };
 
 #endif // HELPER_H