Base: split export/import macros from FCConfig.h and move them to FCGlobal.h

The FCGlobal.h can be included in a Global.h header file of an extension module.

The reason is that some IDEs (e.g. QtCreator) fails to detect the export/import macros when only defined in the PreCompiled.h files and thus raise a parser warning.

src/Mod/Image/App/ImageBase.h

@@ -18,6 +18,8 @@
 #ifndef IMAGEBASE_H
 #define IMAGEBASE_H
 
+#include <Mod/Image/ImageGlobal.h>
+
 namespace Image
 {
 

src/Mod/Image/App/ImagePlane.h

@@ -27,6 +27,7 @@
 #include <App/GeoFeature.h>
 #include <App/PropertyFile.h>
 #include <App/PropertyUnits.h>
+#include <Mod/Image/ImageGlobal.h>
 
 namespace Image
 {