Merge pull request #647 from kubark42/gyro-temperature-referecnce-frame-fix

Gyro temperature reference frame fix
Add style sheet for inverted horizontal sliders.
Refactored input and output channel reversing. This involved
simplifying the code, as well as removing checkboxes and
replacing with less ambiguous visual clues.
Remove unused reverse button.
Added swap icon.
Added reverse icon button.