Removed * properties in panel, since setting the margin screwed with Chosen widgets. This also serves to make the forms a little bit more compact
Changed "Ingredient seizoen" field on toevoegen.html to use Chosen widget
Updated hoeveelheid form in recept toevoegen form. The select box is a Chosen select widget with the allow_single_deselect option. toevoegen function in views.py can now also handle empty entries in the hoeveelheid formset.