CatalogueUI : fix crashes that occur when removing multiple images quickly
CatalogueUI : fix crashes that occur when removing multiple images quickly

lucienfostier/gaffer,ivanimanishi/gaffer,lucienfostier/gaffer,lucienfostier/gaffer,boberfly/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,ImageEngine/gaffer,johnhaddon/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,ivanimanishi/gaffer,appleseedhq/gaffer,ivanimanishi/gaffer,boberfly/gaffer,boberfly/gaffer,appleseedhq/gaffer,ImageEngine/gaffer,hradec/gaffer,andrewkaufman/gaffer,lucienfostier/gaffer,hradec/gaffer,ivanimanishi/gaffer,andrewkaufman/gaffer,boberfly/gaffer,andrewkaufman/gaffer,appleseedhq/gaffer,johnhaddon/gaffer,ImageEngine/gaffer,GafferHQ/gaffer,GafferHQ/gaffer,hradec/gaffer,hradec/gaffer,johnhaddon/gaffer,GafferHQ/gaffer,andrewkaufman/gaffer,hradec/gaffer