Allow TaskThreads to be created while Celluloid shutdown
Allow TaskThreads to be created while Celluloid shutdown

mehta/celluloid,davydovanton/celluloid,olleolleolle/celluloid,kenichi/celluloid,TiagoCardoso1983/celluloid,marshall-lee/celluloid,sideci-sample/sideci-sample-celluloid,seuros/celluloid,jstoja/celluloid,dilumn/celluloid,jasonm23/celluloid,celluloid/celluloid