Remove 'unit' field and header
Remove 'unit' field and header

The last commits bring some improvements to the rendering of formsets,
specially in the workout log form and were cherry picked from the
'rep-options' branch which brings units to logs but will not be ready for the
1.7 release.

kjagoo/wger_stark,kjagoo/wger_stark,petervanderdoes/wger,DeveloperMal/wger,petervanderdoes/wger,DeveloperMal/wger,wger-project/wger,DeveloperMal/wger,rolandgeider/wger,wger-project/wger,rolandgeider/wger,wger-project/wger,petervanderdoes/wger,kjagoo/wger_stark,kjagoo/wger_stark,petervanderdoes/wger,rolandgeider/wger,wger-project/wger,rolandgeider/wger,DeveloperMal/wger