Fixed some rare support issues connected with the 1st print layer.

Fixed support issue, where the XY gap was ignored for the top contact layers
and a fixed 50% was used instead.

xs/src/libslic3r/SupportMaterial.hpp

@@ -226,6 +226,8 @@ private:
 	Flow 			 	 m_first_layer_flow;
 	Flow 			 	 m_support_material_flow;
 	Flow 			 	 m_support_material_interface_flow;
+	// Is merging of regions allowed? Could the interface & base support regions be printed with the same extruder?
+	bool 				 m_can_merge_support_regions;
 
     coordf_t 			 m_support_layer_height_min;
 	coordf_t		 	 m_support_layer_height_max;