implemented creation of certain image type and alo button for setting poylgon data

TODO implement setPolygon function

src/Layer/PaintingArea.h

@@ -115,6 +115,11 @@ void setLayerActive(int idx);
  * \param alpha     - New alpha value of the layer
  */
 void setLayerAlpha(int idx, int alpha);
+/*!
+ * \brief setPolygon is used for setting polygondata, it only works on RASTER images
+ * \param idx - represents the number of the layer with should be transformed
+ */
+void setPolygon(int idx);
 /*!
  * \brief The floodFill method fills a the active layer with a given color
  * \param r     - Red value of the color the layer should be filled with