OP-1351 simplified thermal progress bar handling and made it indeterminate when target duration not yet estimated
OP-1351 made sure that progress bar won't show 100% when calibration failed
OP-1351 display thermal calibration estimated duration in instruction text box
OP-1351 made instruction text more consistent accross calibration steps
OP-1351 moved calibration help text to its own tab (plenty of room to add more help..)