Fixed more input accessibility issues, also

- Added searchParams based router for easier testing
 - Added more stories to the storybook

stories/FieldFunction.stories.js

@@ -0,0 +1,43 @@
+import React from 'react';
+import FieldFunction from '../src/components/FieldFunction';
+import {action} from '@storybook/addon-actions';
+import {Wrapper} from './ui';
+import {withA11y} from '@storybook/addon-a11y';
+import {latest} from '@mapbox/mapbox-gl-style-spec'
+
+
+export default {
+  title: 'FieldFunction',
+  component: FieldFunction,
+  decorators: [withA11y],
+};
+
+export const Basic = () => {
+  const value = {
+    "property": "rank",
+    "type": "categorical",
+    "default": "#222",
+    "stops": [
+      [
+        {"zoom": 6, "value": ""},
+        ["#777"]
+      ],
+      [
+        {"zoom": 10, "value": ""},
+        ["#444"]
+      ]
+    ]
+  };
+
+  return <div style={{width: "360px"}}>
+    <FieldFunction
+      onChange={() => {}}
+      value={value}
+      errors={[]}
+      fieldName={"Color"}
+      fieldType={"color"}
+      fieldSpec={latest['paint_fill']['fill-color']}
+    />
+  </div>
+};
+