Add dropdown interface (#461)

* Add show-deselect option to v-select

* Add parse-choices util

* Add dropdown interface

* Add allow-other prop to v-select (single only)

* Check for custom state correctly

* Treat empty custom value as null

* Set full-width to true by default for inputs / selects

* Add allow-other support to multiple dropdown

* Upgrade display value to show item count

* Fix custom deletion

* Fix tests

* Pass allow other on in dropdown interface

src/interfaces/toggle/toggle.test.ts

@@ -13,6 +13,9 @@ describe('Interfaces / Toggle', () => {
 	it('Renders a v-checkbox', () => {
 		const component = shallowMount(InterfaceToggle, {
 			localVue,
+			listeners: {
+				input: () => undefined,
+			},
 		});
 
 		expect(component.find(VCheckbox).exists()).toBe(true);