F.FormComponent should support default values for checkboxes

[lazd]

Steps

1. Use F.FormComponent and a form that includes a checkbox.

var Component = new Class({
  extend: F.FormComponent,
  model: Backbone.Model.extend({}),
  template: Handlebars.compile('<input type="checkbox" name="someAttr" value="cowValue"><button>Submit</button>')
});

1. Load a model that has someAttr: cowValue.
2. Load the form, uncheck the checkbox, hit save.

Result

someAttr remains as cowValue.

Expected

someAttr should be unset? Set to a different value?

Analysis

When the checkbox is checked, the attribute someAttr is correctly updated with the property: value, when the checkbox is not checked, the property someAttr is untouched