(UTF8 string) In SnapImage,SnapImage cmd failed when an name has UTF8 str.

[tkbd]

How to recreate this problem?

1. Made a primitive,and "Tools > SnapImage" for into SnapImage mode.
   
2. Choose an Image (The Image name is for example "仔猫画像kitten_img")
   
3. Switch Face selection Mode, Select some faces on the primitive.
   
4. Open RMB menu,and do "Snap Image" command.
   
5. Texture snapping failed,and output a following error log.
   

Code:

wpc_snap:command/3: bad return value: {'EXIT',
                                       {badarg,
                                        [{erlang,list_to_atom,
                                          [[100,101,102,97,117,108,116,95,
                                            20180,29483|...]],
                                          []},
                                         {wpc_snap,dup_mat,3,
                                          [{file,"wpc_snap.erl"},{line,382}]},
                                         {wpc_snap,'-set_materials/2-fun-0-',
                                          7,
                                          [{file,"wpc_snap.erl"},{line,363}]},
                                         {wings_face,fold_faces_1,7,
                                          [{file,"wings_face.erl"},
                                           {line,359}]},
                                         {wings_face,fold_faces,4,
                                          [{file,"wings_face.erl"},
                                           {line,349}]},
                                         {wings_sel,mapfold_1,6,
                                          [{file,"wings_sel.erl"},{line,98}]},
                                         {wings_sel,mapfold,3,
                                          [{file,"wings_sel.erl"},{line,93}]},
                                         {wpc_snap,set_materials,2,
                                          [{file,[...]},{line,...}]},
                                         {wpc_snap,snap,1,[{file,...},{...}]},
                                         {wings_develop,time_command,2,
                                          [{...}|...]},
                                         {wings_plugin,command,3,[...]},
                                         {wings,raw_command_1,3,...},
                                         {wings,raw_command,...},
                                         {wings_wm,...},
                                         {...}|...]}}

MacOSX 10.11.6
Wings3D 2.1.5