Allow UserInput prompts to be dismissed
Allow UserInput prompts to be dismissed

This is an alternative to PR #543
jettisonjoe/openhtf,jettisonjoe/openhtf,google/openhtf,google/openhtf,ShaperTools/openhtf,ShaperTools/openhtf,fahhem/openhtf,jettisonjoe/openhtf,ShaperTools/openhtf,fahhem/openhtf,fahhem/openhtf,google/openhtf,fahhem/openhtf,ShaperTools/openhtf,google/openhtf,jettisonjoe/openhtf,ShaperTools/openhtf