Setting non-zero min val causes problems with step

[AdaskoTheBeAsT]

Hi,

there is a small problem with setting non-zero min value when rounding is allowed.

Function _forcestepdivisibility should look like

  function _forcestepdivisibility(value) {
          switch (settings.forcestepdivisibility) {
              case 'round':
                  return (Math.round((value - settings.min) / settings.step) * settings.step + settings.min).toFixed(settings.decimals);
              case 'floor':
                  return (Math.floor((value - settings.min) / settings.step) * settings.step + settings.min).toFixed(settings.decimals);
              case 'ceil':
                  return (Math.ceil((value - settings.min) / settings.step) * settings.step + settings.min).toFixed(settings.decimals);
              default:
                  return value;
          }
      }