Example (#4730)

* add tests for example feature
* refactor ParameterRow value setter logic
* aside: fix property access in sampleFromSchema
* prioritize media type examples for OAS3 responses
* use `example` in schema level example
* refactor: move stringify to utils
* prioritize media type examples in OAS3 request bodies
* modify nightwatch config
* fix parameter/response regressions
* reorder and broaden default value sources
* update lockfile

src/core/components/param-body.jsx

@@ -114,7 +114,7 @@ export default class ParamBody extends PureComponent {
     let { value, isEditBox } = this.state
 
     return (
-      <div className="body-param">
+      <div className="body-param" data-param-name={param.get("name")} data-param-in={param.get("in")}>
         {
           isEditBox && isExecute
             ? <TextArea className={ "body-param__text" + ( errors.count() ? " invalid" : "")} value={value} onChange={ this.handleOnChange }/>