Added render of ngModel when min/max changes
Added render of ngModel when min/max changes

This closes #32 and #45

ym/ui-slider,kongx73/ui-slider,angular-ui/ui-slider,asetiyadi/ui-slider,brydar/ui-slider,anoopelias/ui-slider,angular-ui/ui-slider,pallayr/ui-slider,ym/ui-slider,brydar/ui-slider,pallayr/ui-slider,asetiyadi/ui-slider,kongx73/ui-slider,anoopelias/ui-slider