move abr import to main menu, add progress bar

src/brush.h

@@ -20,7 +20,7 @@ public:
     
     std::shared_ptr<Texture2D> m_pattern_texture;
     std::string m_pattern_path;
-    std::string m_texture_thumb_path;
+    std::string m_pattern_thumb_path;
 
     glm::vec4 m_tip_color{0, 0, 0, 1};
     float m_tip_size = .25f;