Changed import workflow

-Rearrange favorites in fs dock with drag and drop
-Removed import -> sub-scene, moved to scenetree contextual menu
-Removed import -> re-import , moved and integrated to FS dock
-Added ability in FS dock to re-import more than one resource
simultaneously
-Added ability to drag from native filesystem explorer to Godot, only
works on Windows though
-Removed scene reimport merge options, never worked well. Eventually
merging materials should be re-added
-Added ability to set custom root node type when importing scenes
-Re-Import is now automatic, can be configured back to manual in editor
settings
-Added resource previews in property list for many resource types

scene/resources/mesh.cpp

@@ -30,7 +30,6 @@
 #include "scene/resources/concave_polygon_shape.h"
 #include "scene/resources/convex_polygon_shape.h"
 #include "surface_tool.h"
-
 static const char*_array_name[]={
 	"vertex_array",
 	"normal_array",
@@ -288,6 +287,7 @@ void Mesh::add_surface(PrimitiveType p_primitive,const Array& p_arrays,const Arr
 
 	triangle_mesh=Ref<TriangleMesh>();
 	_change_notify();
+	emit_changed();
 
 }
 
@@ -387,6 +387,7 @@ void Mesh::surface_remove(int p_idx) {
 	triangle_mesh=Ref<TriangleMesh>();
 	_recompute_aabb();
 	_change_notify();
+	emit_changed();
 }
 
 
@@ -491,6 +492,8 @@ void Mesh::add_surface_from_mesh_data(const Geometry::MeshData& p_mesh_data) {
 
 	surfaces.push_back(s);
 	_change_notify();
+
+	emit_changed();
 }
 
 RID Mesh::get_rid() const {