remove output thread, do it after plug teardown
remove output thread, do it after plug teardown

fahhem/openhtf,ShaperTools/openhtf,grybmadsci/openhtf,amyxchen/openhtf,ShaperTools/openhtf,jettisonjoe/openhtf,jettisonjoe/openhtf,grybmadsci/openhtf,fahhem/openhtf,jettisonjoe/openhtf,google/openhtf,ShaperTools/openhtf,ShaperTools/openhtf,google/openhtf,fahhem/openhtf,google/openhtf,fahhem/openhtf,ShaperTools/openhtf,amyxchen/openhtf,jettisonjoe/openhtf,grybmadsci/openhtf,grybmadsci/openhtf,google/openhtf