Win fixes: don't export nonexported classes and export exported classes.

src/BufferedImage.h

@@ -114,7 +114,7 @@ template<size_t imageDimensions> class BufferedImage {
 typedef BufferedImage<1> BufferedImage1D;
 
 /** @brief Two-dimensional buffered image */
-class BufferedImage2D: public BufferedImage<2> {
+class MAGNUM_EXPORT BufferedImage2D: public BufferedImage<2> {
     public:
         /** @copydoc BufferedImage::BufferedImage */
         inline BufferedImage2D(AbstractTexture::ColorFormat colorFormat, Type type): BufferedImage(colorFormat, type) {}

src/Image.h

@@ -119,7 +119,7 @@ template<size_t imageDimensions> class Image {
 typedef Image<1> Image1D;
 
 /** @brief Two-dimensional image */
-class Image2D: public Image<2> {
+class MAGNUM_EXPORT Image2D: public Image<2> {
     public:
         /** @copydoc Image::Image */
         inline Image2D(AbstractTexture::ColorFormat colorFormat, Type type): Image(colorFormat, type) {}

src/Trade/AbstractMaterialData.h

@@ -26,7 +26,7 @@ namespace Magnum { namespace Trade {
 
 Subclasses provide access to parameters for given material type.
 */
-class MAGNUM_EXPORT AbstractMaterialData {
+class AbstractMaterialData {
     AbstractMaterialData(const AbstractMaterialData& other) = delete;
     AbstractMaterialData(AbstractMaterialData&& other) = delete;
     AbstractMaterialData& operator=(const AbstractMaterialData& other) = delete;

src/Trade/PhongMaterialData.h

@@ -27,7 +27,7 @@ namespace Magnum { namespace Trade {
 /**
 @brief Phong material
 */
-class MAGNUM_EXPORT PhongMaterialData: public AbstractMaterialData {
+class PhongMaterialData: public AbstractMaterialData {
     public:
         /**
          * @brief Constructor