pull out onChange handler for #input_apiKey so it can be called manually

Hi there.  One feature clients have really loved is the ability to exercise the API endpoints with a prepopulated ApiKey if the API is protected with one.  This comes in really handy for marketing purposes - people can play around in a sandbox environment before going through the process of getting a real ApiKey. 

Before the introduction of the ApiKeyAuthorization class, setting the 'apiKey' property when creating SwaggerUi would pre-populate the 'api_key' input and then I just had to use that for generated API calls.

ApiKeyAuthorization is sweet but I'm wondering if we can just pull out the handler for change() on the 'api_key' input so that we can call it after code that sets the 'api_key' value manually?  This is needed since the change() event doesn't fire unless focus is lost on an input - which it doesn't have in this case.  I left in sample commented-out code that shows this.

What do you think?